Artificial environment for efficient uptate of fertilizers and other agrochemicals in soil

ABSTRACT

A unit for delivery of agrochemicals to the roots of a plant comprising one or more root development zones, and one or more agrochemical zones containing at least one agrochemical, wherein the agrochemical zones are formulated to release the at least one agrochemical into the root development zones in a controlled release manner when the root development zones are hydrated, and wherein the weight ratio of the root development zones to the agrochemical zones in a dry unit is 0.05:1 to 0.32:1.

This application claims priority of U.S. Provisional Application No.61/793,697, filed Mar. 15, 2013, the content of which is herebyincorporated by reference in its entirety.

Throughout this application, various publications are referenced,including referenced in parenthesis. Full citations for publicationsreferenced in parenthesis may be found listed at the end of thespecification immediately preceding the claims. The disclosures of allreferenced publications in their entireties are hereby incorporated byreference into this application in order to more fully describe thestate of the art to which this invention pertains.

BACKGROUND OF INVENTION

Current practices and technologies yield poor agrochemical useefficiency by plants due to over application (up to 50%) (Shaviv andMikkelsen 1993). Excessive application of agrochemicals has adverseeffects on the environment and is costly for farmers (Shaviv andMikkelsen 1993). Additionally, many soils and climates are not suitablefor growing crops (Habarurema and Steiner, 1997; Nicholson and Farrar,1994).

New practices and technologies are needed for efficient application offertilizers and other agrochemicals for improving plant growth.

SUMMARY OF THE INVENTION

The invention provides a unit for delivery of agrochemicals to the rootsof a plant comprising:

-   -   i) one or more root development zones, and    -   ii) one or more agrochemical zones containing at least one        agrochemical,    -   wherein the agrochemical zones are formulated to release the at        least one agrochemical into the root development zones in a        controlled release manner when the root development zones are        swelled, and    -   wherein the weight ratio of the root development zones to the        agrochemical zones in a dry unit is 0.05:1 to 0.32:1.

The invention provides a unit for delivery of agrochemicals to the rootsof a plant comprising:

-   -   i) one or more root development zones, and    -   ii) one or more agrochemical zones containing at least one        agrochemical,    -   wherein the agrochemical zones are formulated to release the at        least one agrochemical into the root development zones in a        controlled release manner when the root development zones are        swelled, and    -   wherein the total volume of the root development zones in the        unit is at least 0.2 mL when the unit is fully swelled.

The invention provides a method of growing a plant, comprising adding atleast one unit of the invention to the medium in which the plant isgrown.

The invention provides a method of reducing environmental damage causedby an agrochemical, comprising delivering the agrochemical to the rootof a plant by adding at least one unit of the invention to the medium ofthe plant.

The present invention provides a method of minimizing exposure to anagrochemical, comprising delivering the agrochemical to the root of aplant by adding at least one unit of the invention to the medium of theplant.

The present invention provides a method of generating an artificial zonewith predetermined chemical properties within the root zone of a plant,comprising:

-   -   i) adding one or more units of the invention to the root zone of        the plant; or    -   ii) adding at one or more units of the invention to the        anticipated root zone of the medium in which the plant is        anticipated to grow.

The present invention provides a method of increasing the growth rate ofa plant, comprising (i) adding one or more units of the invention to amedium where the plant is growing or is to be grown, and (ii) growingthe plant, wherein the plant grows faster in the medium containing theunits than in the medium not containing the units.

The present invention provides a method of increasing the size of aplant, comprising (i) adding one or more units of the invention to amedium where the plant is growing or is to be grown, and (ii) growingthe plant, wherein the plant grows larger in the medium containing theunits than in the medium not containing the units.

The present invention provides a method of increasing N, P, K, and/ormicronutrient (e.g. Zn, Fe, Cu) uptake by a plant, comprising (i) addingone or more units of the invention to a medium where the plant isgrowing or is to be grown, and (ii) growing the plant, wherein the N, P,and/or K uptake of the plant is greater in the medium containing theunits than in the medium not containing the units.

The present invention provides a method of protecting a plant from lowambient temperatures, comprising (i) adding one or more units of theinvention to a medium where the plant is growing or is to be grown, and(ii) growing the plant, wherein plants grown in the medium containingthe units have greater survival rates under low ambient temperaturesthan plants grown in the medium not containing the units.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Swelling behavior of semi-synthetic hydrated SAPs followinghydration and rehydration cycles in water.

FIG. 2. Swelling behavior of hydrated SAPs following hydration andrehydration cycles in sandy soil.

FIG. 3. Swelling behavior of hydrated SAPs following hydration andrehydration cycles in sandy soil loose soil.

FIG. 4. Dissolved oxygen level in the water reservoir opposite theoxygen saturated water.

FIG. 5. Silica coating process on poly sugar beads.

FIG. 6. Beehive like structure made by the Bentonite filler.

FIG. 7. Schematic illustration of the hybrid encapsulation method.

FIG. 8. Release of nitrate from internal zone without (left bars) andwith (right bars) Silica coating.

FIG. 9. Release of PO₄ from internal zone incorporated with Bentonitefiller over time.

FIG. 10A-G. (A) Pea roots growth in CMC—Lab. (B) Corn roots growth inAlginate—Lab. (C) Pea root growth in k-Carrageenan—Lab. (D) Pea rootgrowth on CMC—Lab. (E) Corn root grown in Fully synthetic—Lab. (F) Cornroot grown in Fully synthetic—Lab. (G) Corn roots growth inAlginate—Lab.

FIG. 11. Phase 1: Banding and incorporating dry “beads”, made from anexternal zone (hydrogel) and internal zone (coated minerals) into theupper soil profile. Phase 2: Following watering, the beads swell (up to,e.g., 5 cm in diameter) and agrochemicals diffuse to the external zone &soil. Phase 3: Roots grow and are sustained in/near the external zone,and uptake lasts a few weeks (6-8).

FIG. 12. Non-limiting examples of bead content and dimensions.

FIG. 13. Dissolved Oxygen System.

FIG. 14. The field plot experimental setup of Example 3.

FIG. 15. Soil temperatures at the experimental site of Example 3. Topline shows maximum soil temperatures and bottom line shows minimum soiltemperatures.

FIG. 16. Relative weight of the hydrogels and water application overtime in Example 3.

FIG. 17. Final surface areas of the hydrogel units of Example 3.

FIG. 18. Surface areas of the hydrogel units of Example 3 over time.

FIG. 19. Final surface area to volume ratio of the hydrogel units ofExample 3.

FIG. 20. Final minimal distance values of the hydrogel units of Example3.

FIG. 21. Minimal distance of the hydrogel units of Example 3 versustime.

FIG. 22. Final stiffness values of the hydrogel units of Example 3.

FIG. 23. Stiffness of the hydrogel units of Example 3 versus time.

FIG. 24A-I. Photos of the hydrogels of Example 3 from plots A-C at theend of the experiment. FIG. 24A: fully synthetic; FIG. 24B:Semisynthetic CMC 6% AAm; FIG. 24C: Semisynthetic CMC 6% AA; FIG. 24D:Semisynthetic CMC 25% AA; FIG. 24E: Semisynthetic CMC 50% AA; FIG. 24F:Polysugars Alginate; FIG. 24G: Semisynthetic CMC 6% AAm-Large; FIG. 24H:Semisynthetic CMC 50% AA-large; FIG. 24I: Semisynthetic CMC 6%AAm-Small.

FIG. 25A-I. Photos of the hydrogels of Example 3 from plot D at the endof the experiment. Left panels of FIGS. 25A-G show hydrogels in situ.Right panels of FIGS. 25A-G show samples where roots penetrated throughthe hydrogel. FIG. 25A: fully synthetic; FIG. 25B: Semisynthetic CMC 6%AAm; FIG. 25C: Semisynthetic CMC 6% AA; FIG. 25D: Semisynthetic CMC 25%AA; FIG. 25E: Semisynthetic CMC 50% AA; FIG. 25F: Semisynthetic CMC 6%AAm-Large; FIG. 25G: Semisynthetic CMC 50% AAm-Large; FIG. 25H:Semisynthetic CMC 25% AA; FIG. 25I: Semisynthetic CMC 6% AAm-Large.

FIG. 26. Twenty three rotated weighing lysimeters used in Example 4.

FIG. 27A-B. Dehydrated cylindrical shape fertilizer units of Example 4prior to application (FIG. 27A) and partly hydrated fertilizer units atapplication (FIG. 27B).

FIG. 28. Application dose of N, P, and K per plant for each treatment ofExample 4, stage 1. Slow release: left bars; fertilizer units (Full):middle bars; fertilizer units (Half): right bars.

FIG. 29A-C. Plant height (FIG. 29A), number of leaves (FIG. 29B), andSPAD values (FIG. 29C) of the plants of Example 4, stage 1.

FIG. 30A-C. Plant dry matter (FIG. 30A), absolute NPK uptake amount(FIG. 30B), and NPK uptake efficiency (FIG. 30C) of the plants ofExample 4, stage 1. Fertilizer units (Full): left bars; Fertilizer units(Half): middle bars; Slow release: right bars.

FIG. 31. Relative residuals of N, P, and K in the fertilizer unitsfollowing harvest of the plants of Example 4, stage 1. Fertilizer units(Full): left bars; Fertilizer units (Half): right bars.

FIG. 32A-D. Plant height (FIG. 32A), number of leaves (FIG. 32B), SPADvalues (FIG. 32C), and wet biomass (FIG. 32D) for plants of stage 2 ofExample 4 grown in sandy soil. FIG. 32D: left bars show data for emptyunits plus fertigation (Full) and right bars show data for fertilizerunits (Full).

FIG. 33A-D. Plant height (FIG. 33A), number of leaves (FIG. 33B), SPADvalues (FIG. 33C), and wet biomass (FIG. 33D) for plants of stage 3 ofExample 4 grown in Growing Media. FIG. 33D: left bars show data for SR,middle bars show data for fertilizer units, and right bars show data forfertigation.

FIG. 34A-D. Plant height (FIG. 34A), number of leaves (FIG. 34B), SPADvalues (FIG. 34C), and wet biomass (FIG. 34D) for plants of stage 3 ofExample 4 grown in clayey Media. FIG. 34D: left bars show data forfertilizer units and right bars show data for SR.

FIG. 35A-Q. Photos of fertilizer units and plants at the end of Example4. FIG. 35A: hydrated fertilizer unit; FIG. 35B: root penetration insidehydrated fertilizer unit; FIG. 35C: root distribution within hydratedfertilizer unit; FIG. 35D: root distribution within hydrated fertilizerunit; FIG. 35E: stage 1 fertilizer unit (full); FIG. 35F: stage 1fertilizer unit (half); FIG. 35G: stage 1 SR (full); FIG. 35H:fertilizer unit full (right), fertilizer unit half (left) and SR(middle); FIG. 35I: stage 2 fertilizer unit (full); FIG. 35J: stage 2fertilizer unit (full); FIG. 35K: stage 2 empty unit plus fert.; FIG.35L: stage 2 empty unit plus fert.; FIG. 35M: stage 3 growing media andfertilizer unit; FIG. 35N: stage 3 growing media and SR; FIG. 35O: stage3 growing media and fert.; FIG. 35P: stage 3 clay and fertilizer unit;FIG. 35Q: stage 3 clay and SR.

FIG. 36. Plot design of Example 5.

FIG. 37A-E. Measured parameters throughout the growing season for plantsof Example 5. FIG. 37A: sunflower height; FIG. 37B: sunflower number ofleaves; FIG. 37C: sunflower chlorophyll content optical sensor-SPADvalues; FIG. 37D: cabbage leaves diameter; FIG. 37E: cabbage number ofleaves.

FIG. 38A-B. Macro-nutrient (N, P, and K) content in sunflower andcabbage leaves of Example 5. Left bars show data for fertilizer units,middle bars show data for SR, and right bars show data for fertigation.

FIG. 39A-B. FIG. 39A: ratio between cabbage head diameter and weight incabbage plants of Example 5; FIG. 39B: calculated cabbage head weightover the growing season of Example 5.

FIG. 40. Cabbage dry matter and N-uptake in the cabbage plants ofExample 5. FIG. 40A: final cabbage dry matter per plant in threesubplots; FIG. 40B: cabbage nitrogen uptake per plant in three subplots.Left bars show data for fertilizer units, middle bars show data for SR,and right bars show data for Fertigation.

FIG. 41. Sunflower grain yield and nitrogen uptake per meter in the 3subplots of Example 5. Left bars show data for fertilizer units, middlebars show data for SR, and right bars show data for fertigation.

FIG. 42. NPK residuals in fertilizer units for each plot and crop ofExample 5; FIG. 42A: cabbage; FIG. 42B: sunflower. Left bars show datafor plot 1, middle bars show data for plot 2, and right bars show datafor plot 3.

FIG. 43. Final N soil content in the root zone (>30 cm) for each crop ofExample 5. Left bars show data for sunflower and right bars show datafor cabbage.

FIG. 44A-H. Calculated N mass balance in the root zone of cabbage andsunflower plots of Example 5. FIG. 44A: fertilizer unit, SR, and Fertinitial N mass balance for cabbage plots; FIG. 44B: fertilizer unitfinal N balance for cabbage plots; FIG. 44C: SR final N balance forcabbage plots; FIG. 44D: Fert final N balance for cabbage plots; FIG.44E: fertilizer unit, SR, and Fert initial N mass balance for sunflowerplots; FIG. 44F: fertilizer unit final N balance for sunflower plots;FIG. 44G: SR final N balance for sunflower plots; FIG. 44H: Fert final Nbalance for sunflower plots.

FIG. 45A-C. Photographs showing the hydrated fertilizer units of Example5. FIG. 45A: hydrated fertilizer unit; FIG. 45B: root distributionaround hydrated fertilizer units; FIG. 45C: Root penetration insidehydrated fertilizer unit.

FIG. 46. Fertilizer units made according to the process of Example 6.

FIG. 47. A fully swelled fertilizer unit made according to the processof Example 6 compared to a dried fertilizer unit made according to theprocess of Example 6.

FIG. 48. Combined marketable yield of lettuce and celery from the cropsof Example 8 fertilized with fertilizer units or solid fertilizer.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a unit for delivery of agrochemicals to the rootsof a plant comprising:

-   -   i) one or more root development zones, and    -   ii) one or more agrochemical zones containing at least one        agrochemical,    -   wherein the agrochemical zones are formulated to release the at        least one agrochemical into the root development zones in a        controlled release manner when the root development zones are        swelled, and    -   wherein the weight ratio of the root development zones to the        agrochemical zones in a dry unit is 0.05:1 to 0.32:1.

In some embodiments, the total volume of the root development zones inthe unit is at least 0.2 mL when the unit is fully swelled.

The invention provides a unit for delivery of agrochemicals to the rootsof a plant comprising:

-   -   i) one or more root development zones, and    -   ii) one or more agrochemical zones containing at least one        agrochemical,    -   wherein the agrochemical zones are formulated to release the at        least one agrochemical into the root development zones in a        controlled release manner when the root development zones are        swelled, and    -   wherein the total volume of the root development zones in the        unit is at least 0.2 mL when the unit is fully swelled.

In some embodiments, the weight ratio of the root development zones tothe agrochemical zones in a dry unit is 0.05:1 to 0.32:1.

In some embodiments, the weight ratio of the root development zones tothe agrochemical zones in a dry unit is 0.05:1, 0.1:1, 0.15:1, 0.2:1,0.25:1, or 0.3:1.

In some embodiments, the weight ratio of the root development zones tothe agrochemical zones in a dry unit is 0.01:1 to 0.5:1, 0.01:1 to0.02:1, 0.01:1 to 0.03:1, 0.01:1 to 0.04:1, 0.01:1 to 0.05:1, 0.3:1 to0.4:1, 0.3:1 to 0.4:1, 0.3:1 to 0.5:1.

In some embodiments, the total volume of the root development zones inthe unit is at least 0.2 mL, 0.5 mL, at least 1 mL, at least 2 mL, atleast 5 mL, at least 10 mL, at least 20 mL, at least 30 mL, at least 40mL, at least 50 mL, at least 60 mL, at least 70 mL, at least 80 mL, atleast 90 mL, at least 100 mL, at least 150 mL, at least 200 mL, at least250 mL, at least 300 mL, at least 350 mL, at least 400 mL, at least 450mL, at least 500 mL, at least 550 mL, at least 600 mL or larger than 600mL when the unit is 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%,1-50%, or 5-50% swelled.

In some embodiments, the total volume of the root development zones inthe unit is at least 2 mL when the unit is 1%, 5%, 10%, 15%, 20%, 25%,30%, 35%, 40%, 45%, 50%, 1-50%, or 5-50% swelled.

In some embodiments, the total volume of the root development zones inthe unit is greater than 2 mL, 2-3 mL, 3-4 mL, 4-5 mL, 2-5 mL, 2-10 mL,5-10 mL, 5-20 mL, 10-15 mL, 10-20 mL, 15-20 mL, 10-40 mL, 20-40 mL,20-80 mL, 40-80 mL, 50-100 mL, 75-150 mL, 100-150 mL, 150-300 mL,200-400 mL, 300-600 mL, or 600-1000 mL when the unit is 1%, 5%, 10%,15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 1-50%, or 5-50% swelled.

In some embodiments, the total volume of the root development zones inthe unit is at least 0.2 mL, at least 0.5 mL, at least 1 mL, at least 2mL, at least 5 mL, at least 10 mL, at least 20 mL, at least 30 mL, atleast 40 mL, at least 50 mL, at least 60 mL, at least 70 mL, at least 80mL, at least 90 mL, at least 100 mL, at least 150 mL, at least 200 mL,at least 250 mL, at least 300 mL, at least 350 mL, at least 400 mL, atleast 450 mL, at least 500 mL, at least 550 mL, at least 600 mL orlarger than 600 mL when the unit is fully swelled.

In some embodiments, the total volume of the root development zones inthe unit is at least 2 mL when the unit is fully swelled.

In some embodiments, the total volume of the root development zones inthe unit is greater than 2 mL, 2-3 mL, 3-4 mL, 4-5 mL, 2-5 mL, 2-10 mL,5-10 mL, 5-20 mL, 10-15 mL, 10-20 mL, 15-20 mL, 10-40 mL, 20-40 mL,20-80 mL, 40-80 mL, 50-100 mL, 75-150 mL, 100-150 mL, 150-300 mL,200-400 mL, 300-600 mL, or 600-1000 mL when the unit is fully swelled.

In some embodiments, the total volume of the root development zones whenthe unit is 1%-100% swelled is large enough to contain at least 10 mm ofa root having a diameter of 0.5 mm.

In some embodiments, the total volume of the root development zones whenthe unit is 1-100% swelled is large enough to contain 10-50 mm of a roothaving a diameter of 0.5-5 mm.

In some embodiments, the total volume of the root development zones whenthe unit is 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 1-50%,or 5-50% swelled is large enough to contain at least 10 mm of a roothaving a diameter of 0.5 mm.

In some embodiments, the total volume of the root development zones whenthe unit is 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 1-50%or 5-50% swelled is large enough to contain 10-50 mm of a root having adiameter of 0.5-5 mm.

In some embodiments, the unit has a dry weight of 0.1 g to 20 g.

In some embodiments weight of the dry unit is 1-10 g. In someembodiments, the weight of the dry unit is 1, 2, 3, 4, 5, 6, 7, 8, 9, or10 g.

In some embodiments, the total weight of the agrochemical zones of theunit is 0.05 to 5 grams.

In some embodiments, the unit is in the shape of a cylinder.

In some embodiments, the unit is in the shape of a polyhedron.

In some embodiments, the unit is in the shape of a cube.

In some embodiments, the unit is in the shape of a disc.

In some embodiments, the unit is in the shape of a sphere.

In some embodiments, the agrochemical zones and the root developmentzones are adjoined.

In some embodiments, the unit consists of one root development zonewhich is next to one agrochemical zone.

In some embodiments, the agrochemical zones are partially containedwithin the root development zones such that the surface of the unit isformed by both the root development zones and the agrochemical zones.

In some embodiments, the root development zones are partially containedwithin the agrochemical zones such that the surface of the unit isformed by both the root development zones and the agrochemical zones.

In some embodiments, an agrochemical zone is sandwiched between two rootdevelopment zones.

In some embodiments, the agrochemical zone is surrounded by a rootdevelopment zone which forms a perimeter around the agrochemical zonebut which covers less than all of the surface of the agrochemical zone,or vice versa. In some embodiments, the perimeter is ring shaped.

In some embodiments, the unit is a bead comprising an external zonesurrounding an internal zone, wherein the root development zones formthe external zone and the agrochemical zones form the internal zone.

In some embodiments, the unit comprises one root development zone andone agrochemical zone.

In some embodiments, the root development zones comprise a superabsorbent polymer (SAP).

In some embodiments, the root development zones are capable of absorbingat least about 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 80, 85, 90, 95,100, 200, 300, 400, 500, or 1000 times their weight in water.

In some embodiments, the root development zones are capable of absorbingat least about 20-30 times their weight in water.

In some embodiments, the root development zones are permeable to oxygen.

In some embodiments, the root development zones are permeable to oxygensuch that at least about 6 mg/L of dissolved oxygen is maintained in theroot development zones when the root development zones are swelled.

In some embodiments, the root development zones when fully swelled areat least about 70, 75, 80, 85, 90, 95, or 100% as permeable to oxygen asswelled alginate or swelled semi-synthetic CMC.

In some embodiments, the root development zones comprise an aerogel, ahydrogel or an organogel.

In some embodiments, the root development zones comprise a hydrogel.

In some embodiments, the root development zones comprise an aerogel.

In some embodiments, the root development zones comprise a geotextile.

In some embodiments, the root development zones comprise a sponge.

In some embodiments, the wherein the root development zones furthercomprise a polymer, a porous inorganic material, a porous organicmaterial, or any combination thereof.

In some embodiments, the agrochemical zones further comprise an aerogel,a hydrogel, an organogel, a polymer, a porous inorganic material, aporous organic material, or any combination thereof.

In some embodiments, roots of a plant are capable of penetrating theroot development zones when the root development zones are about 1%, 5%,10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 1-50% or 5-50% swelled.

In some embodiments, roots of a plant are capable of growing within theroot development zones when the root development zones are swelled.

In some embodiments, roots of a plant are capable of growing within theroot development zones when the root development zones are about 1%, 5%,10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 1-50% or 5-50% swelled.

In some embodiments, microbes are capable of penetrating and growingwithin the root development zones when the root development zones areswelled.

In some embodiments, the plant is a crop plant.

In some embodiments, the crop plant is a wheat plant, a maize plant, asoybean plant, a rice plant, a barley plant, a cotton plant, a peaplant, a potato plant, a tree crop plant, or a vegetable plant.

In some embodiments, the root development zones are capable of repeatedswelling cycles that each comprises hydration followed by dehydration.

In some embodiments, the root development zones are capable of repeatedswelling cycles in soil that each comprise hydration followed bydehydration while in the soil.

In some embodiments, the unit is in the shape of a sphere or anequivalent polyhedron.

In some embodiments, the unit is in the shape of a sphere or anequivalent polyhedron after repeated swelling cycles.

In some embodiments, the root development zones, when swelled, maintainat least about 75%, 80%, 85%, 90%, or 95% of their water content over aperiod of at least about 25, 50, 100, or 150 hours in soil.

In some embodiments, the root development zones, when swelled, maintainat least about 75%, 80%, 85%, 90%, or 95% of their water content over aperiod of at least about 25, 50, 100, or 150 hours in sandy soil.

In some embodiments, the root development zones, when swelled, maintainat least about 75%, 80%, 85%, 90%, or 95% of their volume over a periodof at least about 25, 50, 100, or 150 hours in soil.

In some embodiments, the root development zones, when swelled, maintainat least about 75%, 80%, 85%, 90%, or 95% of their volume over a periodof at least about 25, 50, 100, or 150 hours in sandy soil.

In some embodiments, the root development zones, when swelled, maintaintheir shape over a period of at least about 25, 50, 100, or 150 hours insoil.

In some embodiments, the root development zones, when swelled, maintaintheir shape over a period of at least about 25, 50, 100, or 150 hours insandy soil.

In some embodiments, the root development zones, when swelled, maintaintheir shape after repeated swelling cycles that each comprises hydrationfollowed by dehydration.

In some embodiments, the root development zones, when swelled maintaintheir shape after at least 3 swelling cycles that each compriseshydration followed by dehydration.

In some embodiments, the root development zones are biodegradable.

In some embodiments, the root development zones, when swelled in soil,have a pH or osmotic pressure that differs from the pH or osmoticpressure of the surrounding soil by at least about 10%.

In some embodiments, the root development zones do not contain the atleast one agrochemical before the unit is swelled for the first time.

In some embodiments, the root development zones further comprise the atleast one agrochemical before the unit is swelled for the first time.

In some embodiments, the amount of the at least one agrochemical in theroot development zones is about 5%, 10%, 15% or 20% (w/w) of the amountof the at least one agrochemical that is in the agrochemical zones.

In some embodiments, the widest part of the unit is about 1, 2, 3, 4, 5,6, 7, 8, 9, 10 cm, or more than 10 cm when the root development zonesare about 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 1-50% or5-50% swelled.

In some embodiments, when the root development zones are about 5%, 10%,15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or 5-50% swelled, the totalweight of the root development zones is at least about 2, 3, 4, 5, 6, 7,8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 or more than 100 timesgreater than the total weight of the agrochemical zones.

In some embodiments, the root development zones comprise a synthetichydrogel, a natural carbohydrate hydrogel, or a pectin or proteinhydrogel, or any combination thereof.

In some embodiments, the synthetic hydrogel comprises acrylamide, anacrylic derivative, or any combination thereof.

In some embodiments, the natural carbohydrate hydrogel comprises agar,cellulose, chitosan, starch, hyaluronic acid, a dextrine, a natural gum,a sulfated polysaccharide, or any combination thereof.

In some embodiments, the pectin or protein hydrogel comprises gelatin, agelatin derivative, collagen, a collagen derivative, or any combinationthereof.

In some embodiments, the root development zones comprise a natural superabsorbent polymer (SAP), a poly-sugar SAP, a semi-synthetic SAP, afully-synthetic SAP, or any combination thereof.

In some embodiments, the root development zones comprise a combinationof at least one natural SAP and at least one semi-synthetic or syntheticSAP.

In some embodiments, the root development zones comprise a poly-sugarSAP.

In some embodiments, the poly-sugar SAP is alginate.

In some embodiments, the alginate is at least about 0.2% alginate.

In some embodiments, the root development zones comprise asemi-synthetic SAP.

In some embodiments, the semi-synthetic SAP is a CMC-g-polyacrylic acidSAP.

In some embodiments, the Caboxymethyl cellulose (CMC) graftedpolyacrylic acid SAP comprises 6% CMC relative to the acrylic monomers(Acrylamide-acrylic), 6% CMC relative to acrylic acid, 25% CMC relativeto acrylic acid, or CMC 50% AA.

In some embodiments, the CMC grafted SAP comprises 5-50% CMC relativethe acrylic monomers.

In some embodiments, the CMC grafted SAP comprises 6-12% CMC relativethe acrylic monomers.

In some embodiments, the semi-synthetic SAP is k-carrageenancross-linked-polyacrylic acid SAP.

In some embodiments, the SAP is other than alginate or a k-carrageenancross-linked-polyacrylic acid SAP.

In some embodiments, the root development zones comprise a fullysynthetic SAP.

In some embodiments, the fully synthetic SAP is acrylic acid or acrylicamide or any of the combinations thereof.

In some embodiments, the amount of cross-linker in the root developmentzones is below 5% relative to the total monomer content by weight. Insome embodiments, the amount of cross-linker in the root developmentzones is below 2% relative to the total monomer content by weight. Insome embodiments, the amount of cross-linker in the root developmentzones is below 1% relative to the total monomer content by weight.

In some embodiments, the polymer content of a swelled unit is below 5%by weight. In some embodiments, the polymer content of a swelled unit isbelow 4%, below 3%, below 2%, or below 1% by weight.

In some embodiments, the root development zones further comprise atleast one oxygen carrier that increases the amount of oxygen in the rootdevelopment zones compared to corresponding root development zones notcomprising the oxygen carrier.

In some embodiments, the at least one oxygen carrier is aperfluorocarbon.

In some embodiments, the agrochemical zones comprise an organic polymer,a natural polymer, or an inorganic polymer, or any combination thereof.

In some embodiments, the agrochemical zones are partially or fullycoated with a coating system.

In some embodiments, the coating system dissolves into the rootdevelopment zones when the root development zones are swelled.

In some embodiments, the coating system slows the rate at which the atleast one agrochemical dissolves into the root development zones whenthe root development zones are swelled.

In some embodiments, the units comprise a coating system which coversall surfaces of the agrochemical zones which would otherwise be on thesurface of the unit and which is impermeable to the at least oneagrochemical.

In some embodiments, the coating system is silicate or silicon dioxide.

In some embodiments, the coating system is a polymer.

In some embodiments, the coating system is an agrochemical.

In some embodiments, the agrochemical zones comprise a polymer.

In some embodiments, the polymer is a highly cross-linked polymer.

In some embodiments, the highly cross-linked polymer is a poly-sugar ora poly-acrylic polymer.

In some embodiments, the agrochemical zones comprises a filler.

In some embodiments, the filler comprises a cellulosic material, acellite, a polymeric material, a silicon dioxide, a phyllosilicate, aclay mineral, metal oxide particles, porous particles, or anycombination thereof.

In some embodiments, the filler comprises a phyllosilicate of theserpentine group.

In some embodiments, the a phyllosilicate of the serpentine group isantigorite (Mg₃Si₂O₅(OH)₄), chrysotile (Mg₃Si₂O₅(OH)₄), or lizardite(Mg₃Si₂O₅(OH)₄).

In some embodiments, the filler comprises a clay mineral, which ishalloysite (Al₂Si₂O₅(OH)₄), kaolinite (Al₂Si₂O₅(OH)₄), illite((K,H₃O)(Al,Mg,Fe)₂(Si,Al)₄O₁₀[(OH)₂,(H₂O)]), montmorillonite((Na,Ca)_(0.33)(Al,Mg)₂Si₄O₁₀(OH)₂.nH₂O), vermiculite((MgFe,Al)₃(Al,Si)₄O₁₀(OH)₂.4H₂O), talc (Mg₃Si₄O₁₀(OH)₂), palygorskite((Mg,Al)₂Si₄O₁₀(OH).4(H₂O), or pyrophyllite (Al₂Si₄O₁₀(OH)₂).

In some embodiments, the filler comprises a phyllosilicate of the micagroup.

In some embodiments, the phyllosilicate of the mica group is biotite(K(Mg,Fe)₃(AlSi₃)O₁₀(OH)₂), muscovite (KAl₂(AlSi₃)O₁₀(OH)₂), phlogopite(KMg₃(AlSi₃)O₁₀(OH)₂), lepidolite (K(Li,Al)₂₋₃(AlSi₃)O₁₀(OH)₂),margarite (CaAl₂(Al₂Si₂)O₁₀(OH)₂), glauconite((K,Na)(Al,Mg,Fe)₂(Si,Al)₄O₁₀(OH)₂), or any combination thereof.

In some embodiments, the filler comprises a phyllosilicate of thechlorite group.

In some embodiments, the a phyllosilicate of the chlorite group ischlorite ((Mg,Fe)₃(Si,Al)₄O₁₀(OH)₂.(Mg,Fe)₃(OH)₆).

In some embodiments, the filler forms a beehive-like structure.

In some embodiments, the beehive-like structure is microscopic.

In some embodiments, the filler comprises clay.

In some embodiments, the filler comprises zeolite.

In some embodiments, the agrochemical zones comprise at least about0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 grams of the atleast one agrochemical.

In some embodiments, the agrochemical zones comprise 1-10 grams of theat least one agrochemical.

In some embodiments, the agrochemical zones are about 30%, 35%, 40%,45%, 50%, 55%, or 60% of the at least one agrochemical by weight.

In some embodiments, the agrochemical zones are biodegradable.

In some embodiments, the unit comprises one agrochemical zone.

In some embodiments, the unit comprises 2, 3, 4, 5, 6, 7, 8, 9, 10 ormore than 10 agrochemical zones.

In some embodiments, the unit comprises 2, 3, 4, 5, 6, 7, 8, 9, 10 ormore than 10 root development zones.

In some embodiments, the at least one agrochemical is:

-   -   i) at least one fertilizer compound;    -   ii) at least one pesticide compound,    -   iii) at least one hormone compound;    -   iv) at least one drug compound;    -   v) at least one chemical growth agents;    -   vi) at least one enzyme;    -   vii) at least one growth promoter; and/or    -   viii) at least one microelement.

In some embodiments, the at least one fertilizer compound is a naturalfertilizer.

In some embodiments, the at least one fertilizer compound is a syntheticfertilizer.

In some embodiments, the at least one pesticide compound is:

-   -   i) at least one insecticide compound;    -   ii) at least one nematicide compound;    -   iii) at least one herbicide compound; and/or

iv) at least one fungicide compound.

In some embodiments, the at least one insecticide compound isimidacloprid.

In some embodiments, the at least one herbicide compound ispendimethalin.

In some embodiments, the at least one fungicide compound isazoxystrobin.

In some embodiments, the at least one nematicide compound isfluensulfone.

In some embodiments, the at least one fertilizer compound is PO₄, NO₃,(NH₄)₂SO₂, NH₄H₂PO₄, and/or KCl.

In some embodiments, the at least one fertilizer compound comprisesmultiple fertilizer compounds which include PO₄, NO₃, (NH₄)₂SO₂,NH₄H₂PO₄, and/or KCl.

In some embodiments, the at least one agrochemical is at least onefertilizer compound and at least one pesticide compound.

In some embodiments, the at least one agrochemical is at least onepesticide compound.

In some embodiments, the at least one agrochemical is at least onefertilizer compound.

In some embodiments, the at least one pesticide compound is at least onepesticide compound that is not suitable for application to anagricultural field.

In some embodiments, the at least one pesticide compound that is notsuitable for application to an agricultural field is too toxic to beapplied to an agricultural field.

In some embodiments, the at least one pesticide compound is toxic toanimals other than arthropods or mollusks when applied to anagricultural field in an amount that is sufficient to kill an arthropodor a mollusk.

In some embodiments, the at least one agrochemical is released from theagrochemical zones over a period of at least about one week when theroot development zones are swelled.

In some embodiments, the at least one agrochemical is released from theagrochemical zones into the root development zones over a period of atleast about 2, 3, 4, 5, 6, 7, 8, 9, 10, or 20 weeks when the rootdevelopment zones are swelled.

In some embodiments, the at least one agrochemical is released from theagrochemical zones into the root development zones over a period of atleast about 2, 3, 4, 5, 6, 7, 8, 9, 10, or 20 weeks when the rootdevelopment zones are about 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%,45%, 50%, 1-50% or 5-50% swelled.

In some embodiments, when the root development zones are swelled and theunit is in soil, the at least one agrochemical diffuses from the surfaceof the unit into the surrounding soil at a linear rate beginning about25 days after hydration.

In some embodiments, when the root development zones of the unit areswelled and the unit is in soil, the at least one agrochemical diffusesfrom the surface of the unit into the surrounding soil for at leastabout 50 or 75 days after hydration.

In some embodiments, the unit is not swelled.

In some embodiments, the unit contains less than about 35%, 30%, 25%,20%, 15%, or 10% water by weight.

In some embodiments, the unit comprises one or more interface zonebetween the agrochemical zones and the root development zones, whichinterface zone is formed by at least one insoluble salt or solid, atleast one cross-linking agent, or at least one inorganic compound.

In some embodiments, diffusion between the root development zones andthe agrochemical zones is limited by altering the pH or the cationconcentration in the agrochemical zones, the root development zones, orthe interface zone.

In some embodiments, diffusion between the root development zones andthe agrochemical zones is limited by altering the pH and/or cationconcentration in the agrochemical zone or the root development zone.

In some embodiments, the pH in the agrochemical zones or the rootdevelopment zones is altered by a buffer.

In some embodiments, the pH in the agrochemical zones, the interfacezones, and the root development zones is altered by a buffer.

The invention provides a method of growing a plant, comprising adding atleast one unit of the invention to the medium in which the plant isgrown.

In some embodiments, the method comprises a step of selecting the sizeof the unit based upon the specific plant to be grown. For example, itmay be desirable to select a unit having a large swelled size whengrowing a plant having large diameter roots and it may be desirable toselect a unit having a smaller swelled size when growing a plant havingsmall diameter roots. In some embodiments, it may be desirable to usemore units of a given size when growing a plant having a large rootsystem than when growing a plant having a small root system.

In some embodiments, the medium in which the plant is grown comprisessoil.

In some embodiments, the medium in which the plant is grown is soil.

In some embodiments, the soil comprises sand, silt, clay, or anycombination thereof.

In some embodiments, the soil is clay, loam, clay-loam, or silt-loam.

In some embodiments, the soil is an Andisol.

In some embodiments, the at least one unit is added to the soil at oneor more depths below the soil surface. In some embodiments, the at leastone unit is added at a depth of 5-50 cm. In some embodiments, the atleast one unit is added at a depth of 5 cm, 10 cm, 15 cm, 20 cm, 25 cm,30 cm, 35 cm, 40 cm, 45 cm, or 50 cm, or any combination of 2, 3, or 4of the foregoing depths.

The invention provides a method of reducing environmental damage causedby an agrochemical, comprising delivering the agrochemical to the rootof a plant by adding at least one unit of the invention to the medium ofthe plant.

The present invention provides a method of minimizing exposure to anagrochemical, comprising delivering the agrochemical to the root of aplant by adding at least one unit of the invention to the medium of theplant.

In some embodiments, minimizing exposure to the agrochemical isminimizing the exposure of a farmer to the agrochemical.

In some embodiments, minimizing exposure to the agrochemical isminimizing exposure of a person other than the farmer to theagrochemical.

The present invention provides a method of generating an artificial zonewith predetermined chemical properties within the root zone of a plant,comprising:

-   -   i) adding one or more units of the invention to the root zone of        the plant; or    -   ii) adding one or more units of the invention to the anticipated        root zone of the medium in which the plant is anticipated to        grow.

In some embodiments, step i) comprises adding at least two differentunits to the root zone of the plant; and step ii) comprises adding atleast two different units to the anticipated root zone of the medium inwhich the plant is anticipated to grow, wherein at least one of the atleast two different units is a unit of the invention.

In some embodiments, each of the at least two different units containsat least one agrochemical that is not contained within one of the otherat least two different units.

In some embodiments, the plant is grown in a field.

In some embodiments, the plant is a crop plant.

In some embodiments, the crop plant is a grain or a tree crop plant.

In some embodiments, the crop plant is a fruit or a vegetable plant.

In some embodiments, the plant is a banana, barley, bean, cassava, corn,cotton, grape, orange, pea, potato, rice, soybean, sugar beet, tomato,or wheat plant.

In some embodiments, the plant is a sunflower, cabbage plant, lettuce,or celery plant.

The present invention provides a method of increasing the yield of aplant, comprising (i) adding one or more units of the invention to amedium where the plant is growing or is to be grown, and (ii) growingthe plant, wherein the yield of the plant is higher when grown in themedium containing the units than in the medium not containing the units.

The present invention provides a method of increasing the growth rate ofa plant, comprising (i) adding one or more units of the invention to amedium where the plant is growing or is to be grown, and (ii) growingthe plant, wherein the plant grows faster in the medium containing theunits than in the medium not containing the units.

The present invention provides a method of increasing the size of aplant, comprising (i) adding one or more units of the invention to amedium where the plant is growing or is to be grown, and (ii) growingthe plant, wherein the plant grows larger in the medium containing theunits than in the medium not containing the units.

The present invention provides a method of increasing N, P, and/or Kuptake by a plant, comprising (i) adding one or more units of theinvention to a medium where the plant is growing or is to be grown, and(ii) growing the plant, wherein the N, P, and/or K uptake of the plantis greater in the medium containing the units than in the medium notcontaining the units.

The present invention provides a method of protecting a plant from lowambient temperatures, comprising (i) adding one or more units of theinvention to a medium where the plant is growing or is to be grown, and(ii) growing the plant, wherein plants grown in the medium containingthe units have greater survival rates under low ambient temperaturesthan plants grown in the medium not containing the units.

In some embodiments, low ambient temperature is below 15° C., below 12°C., below 10° C., below 8° C., below 6° C., below 4° C., below 2° C., orbelow 0° C.

In some embodiments, the units are added to the medium where the plantis growing.

In some embodiments, the units are added to the medium where the plantis to be grown.

In some embodiments, seeds for growing the plant are added to the mediumbefore the units are added to the medium.

In some embodiments, seeds for growing the plant are added to the mediumat the same time the units are added to the medium.

In some embodiments, seeds for growing the plant are added to the mediumafter the units are added to the medium.

In some embodiments, the medium is soil.

In some embodiments, the units comprise one fertilizer compound. In someembodiments, the units comprise two fertilizer compounds. In someembodiments, the units comprise three fertilizer compounds. In someembodiments, the units comprise more than three fertilizer compounds.

In some embodiments, the units comprise one to three fertilizercompounds, such that the total N, P, and/or K content as (NH₄)₂SO₂,NH₄H₂PO₄, and KCl in the medium as part of the units is about 5-50,1-10, and 5-60 g/m², respectively.

In some embodiments, the units comprise three fertilizer compounds, suchthat the total N, P, and K content as (NH₄)₂SO₂, NH₄H₂PO₄, and KCl inthe medium as part of the units is about 25, 5, and 30 g/m²,respectively.

The invention also provides a method of making a unit of the inventioncomprising encapsulating at least one agrochemical zone within a SAP.

In some embodiments, encapsulating comprises polymerizing the SAP aroundthe at least one agrochemical zone.

In some embodiments, encapsulating comprises a first polymerization stepand a second polymerization step.

In some embodiments, the first polymerization step comprises forming athree dimensional structure of SAP having a cavity into which the atleast one agrochemical zone can be placed, and the second polymerizationstep comprises sealing the cavity with additional SAP.

In some embodiments, the at least one agrochemical zone is placed in thecavity prior to the second polymerization step.

The present invention provides a bead comprising:

-   -   i) an external zone comprising a super absorbent polymer (SAP)        that is capable of absorbing at least about 5 times its weight        in water,        -   surrounding    -   ii) at least one internal zone comprising a core that contains        at least one agrochemical,        wherein the external zone is permeable to oxygen when hydrated,        or the internal zone is formulated to release the at least one        agrochemical into the external zone over a period of at least        about one week when the hydrogel of the external zone is        hydrated.

The present invention provides a bead comprising:

-   -   i) an external zone comprising a super absorbent polymer (SAP)        that is capable of absorbing at least about 5 times its weight        in water,        -   surrounding    -   ii) at least one internal zone comprising a core that contains        at least one agrochemical,        wherein the external zone is permeable to oxygen when hydrated,        and the internal zone is formulated to release the at least one        agrochemical into the external zone over a period of at least        about one week when the hydrogel of the external zone is        hydrated.

In some embodiments, the SAP is capable of absorbing at least about 50,75, 80, 85, 90, 95, 100, 200, 300, 400, 500, or 1000 times its weight inwater.

In some embodiments, the SAP is permeable to oxygen.

In some embodiments, the SAP is permeable to oxygen such that itmaintains at least about 6 mg/L of dissolved oxygen in the SAP when itis hydrated.

In some embodiments, the SAP when fully hydrated is at least about 70,75, 80, 85, 90, 95, or 100% as permeable to oxygen as hydrated alginateor hydrated semi-synthetic CMC.

In some embodiments, the SAP is an aerogel, a hydrogel or an organogel.

In some embodiments, the SAP is a hydrogel.

In some embodiments, the external zone further comprises a polymer, aporous inorganic material, a porous organic material, or any combinationthereof.

In some embodiments, the internal zone further comprises an aerogel, ahydrogel, an organogel, a polymer, a porous inorganic material, a porousorganic material, or any combination thereof.

In some embodiments, roots of a crop plant are capable of penetratingthe hydrogel when the hydrogel is about 1%, 5%, 10%, 15%, 20%, 25%, 30%,35%, 40%, 45%, 50%, 1-50% or 5-50% hydrated.

In some embodiments, roots of a crop plant are capable of penetratingthe hydrogel when the hydrogel is about 1%, 5%, 10%, 15%, 20%, 25%, 30%,35%, 40%, 45%, 50%, 1-50% or 5-50% hydrated.

In some embodiments, roots of a crop plant are capable of growing withinthe hydrogel when the hydrogel is hydrated.

In some embodiments, roots of a crop plant are capable of growing withinthe hydrogel when the hydrogel is about 1%, 5%, 10%, 15%, 20%, 25%, 30%,35%, 40%, 45%, 50%, 1-50% or 5-50% hydrated.

In some embodiments, roots of a crop plant are capable of growing withinthe hydrogel when the hydrogel is hydrated.

In some embodiments, roots of a crop plant are capable of growing withinthe hydrogel when the hydrogel is about 1%, 5%, 10%, 15%, 20%, 25%, 30%,35%, 40%, 45%, 50%, 1-50% or 5-50% hydrated.

In some embodiments, the crop plant is a sunflower plant. In someembodiments, the crop plant is a cabbage plant. In some embodiments, thecrop plant is wheat plant. In some embodiments, the crop plant is maizeplant. In some embodiments, the crop plant is a soybean plant. In someembodiments, the crop plant is a rice plant. In some embodiments, thecrop plant is a barley plant. In some embodiments, the crop plant is acotton plant. In some embodiments, the crop plant is a pea plant. Insome embodiments, the crop plant is a potato plant. In some embodiments,the crop plant is a tree crop plant. In some embodiments, the crop plantis a vegetable plant.

In some embodiments, the hydrogel is capable of repeated swelling cyclesthat each comprises hydration followed by dehydration.

In some embodiments, the hydrogel is capable of repeated swelling cyclesin soil that each comprise hydration followed by dehydration while inthe soil.

In some embodiments, the bead is in the shape of a sphere or anequivalent polyhedron. In some embodiments, the polyhedron is six sided.In some embodiments, the polyhedron is a cube.

In some embodiments, the bead is in the shape of a sphere or anequivalent polyhedron after repeated swelling cycles.

In some embodiments, the bead is in the shape of a cylinder. In someembodiments, the bead is in the shape of a cylinder after repeatedswelling cycles.

In some embodiments, the bead is in the shape of a disc.

In some embodiments, the hydrogel, when hydrated, maintains at leastabout 75%, 80%, 85%, 90%, or 95% of its water content over a period ofat least about 25, 50, 100, or 150 hours in soil.

In some embodiments, the hydrogel, when hydrated, maintains at leastabout 75%, 80%, 85%, 90%, or 95% of its water content over a period ofat least about 25, 50, 100, or 150 hours in sandy soil.

In some embodiments, the hydrogel, when hydrated, maintains at leastabout 75%, 80%, 85%, 90%, or 95% of its volume over a period of at leastabout 25, 50, 100, or 150 hours in soil.

In some embodiments, the hydrogel, when hydrated, maintains at leastabout 75%, 80%, 85%, 90%, or 95% of its volume over a period of at leastabout 25, 50, 100, or 150 hours in sandy soil.

In some embodiments, the hydrogel, when hydrated, maintains its shapeover a period of at least about 25, 50, 100, or 150 hours in soil.

In some embodiments, the hydrogel, when hydrated, maintains sphericalshape over a period of at least about 25, 50, 100, or 150 hours in sandysoil.

In some embodiments, the hydrogel, when hydrated, maintains its shapeafter repeated swelling cycles that each comprises hydration followed bydehydration.

In some embodiments the hydrogel, when hydrated maintains its shapeafter at least 3 swelling cycles that each comprises hydration followedby dehydration.

In some embodiments, the SAP is biodegradable.

In some embodiments, when hydrated in soil, the external zone of thebead has a pH or osmotic pressure that differs from the pH or osmoticpressure of the surrounding soil by at least about 10%.

In some embodiments, the external zone does not contain the at least oneagrochemical before the bead is hydrated for the first time.

In some embodiments, the external zone also contains the at least oneagrochemical.

In some embodiments, the amount of the at least one agrochemical in theexternal zone is about 5%, 10%, 15% or 20% (w/w) of the amount of the atleast one agrochemical that is in the internal zone.

In some embodiments, the bead has a maximum diameter of about 1, 2, 3,4, 5, 6, 7, 8, 9, or 10 cm when the SAP of the external zone is about5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or 5-50% hydrated.

In some embodiments, when the SAP of the external zone is about 5%, 10%,15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or 5-50% hydrated, the weight ofthe external zone is at least about 2, 3, 4, 5, 6, 7, 8, 9, or 10 timesgreater than the weight of the internal zone.

In some embodiments, the hydrogel is a synthetic hydrogel, a naturalcarbohydrate hydrogel, or a pectin or protein hydrogel, or anycombination thereof.

In some embodiments, the synthetic hydrogel comprises acrylamide, anacrylic derivative, or any combination thereof.

In some embodiments, the natural carbohydrate hydrogel comprises agar,cellulose, chitosan, starch, hyaluronic acid, a dextrine, a natural gum,a sulfated polysaccharide, or any combination thereof.

In some embodiments, the pectin or protein hydrogel comprises gelatin, agelatin derivative, collagen, a collagen derivative, or any combinationthereof.

In some embodiments, the hydrogel comprises a natural super absorbentpolymer (SAP), a poly-sugar SAP, a semi-synthetic SAP, a fully-syntheticSAP, or any combination thereof.

In some embodiments, the hydrogel comprises a combination of at leastone natural SAP and at least one semi-synthetic or synthetic SAP.

In some embodiments, the hydrogel comprises a poly-sugar SAP.

In some embodiments, the poly-sugar SAP is alginate.

In some embodiments, the alginate is at least about 0.2% alginate.

In some embodiments, the hydrogel comprises a semi-synthetic SAP.

In some embodiments, the semi-synthetic SAP is a CMC-g-polyacrylic acidSAP.

In some embodiments, the Caboxymethyl cellulose (CMC) graftedpolyacrylic acid SAP comprises 6% CMC relative to the acrylic monomers(Acrylamide-acrylic), 6% CMC relative to acrylic acid, 25% CMC relativeto acrylic acid, or CMC 50% AA.

In some embodiments, the SAP is other than alginate or a k-carrageenancross-linked-polyacrylic acid SAP.

In some embodiments, the SAP is a k-carrageenan cross-linked-polyacrylicacid SAP.

In some embodiments, the hydrogel comprises a fully synthetic SAP.

In some embodiments, the fully synthetic SAP is acrylic acid or acrylicamide or any of the combinations thereof.

In some embodiments, the external zone further comprises at least oneoxygen carrier that increases the amount of oxygen in the external zonecompared to a corresponding external zone not comprising the oxygencarrier.

In some embodiments, the at least one oxygen carrier is aperfluorocarbon.

In some embodiments the internal zone comprises an organic polymer, anatural polymer, or an inorganic polymer, or any combination thereof.

In some embodiments, the at least one core is coated with at least onecoat compound.

In some embodiments, the at least one coat compound dissolves into theSAP when the SAP is hydrated.

In some embodiments, the at least one coat compound slows the rate atwhich the at least one agrochemical dissolves into the SAP when the SAPis hydrated.

In some embodiments, the at least one coat compound is silicate orsilicon dioxide.

In some embodiments, the at least one coat compound is the at least oneagrochemical.

In some embodiments, the at least one core comprises a polymer.

In some embodiments, the polymer is a highly cross-linked polymer.

In some embodiments, the highly cross-linked polymer is a poly-sugar ora poly-acrylic polymer.

In some embodiments, the at least one core comprises a filler.

In some embodiments, the filler comprises a cellulosic material, acellite, a polymeric material, a silicon dioxide, a phyllosilicate, aclay mineral, metal oxide particles, porous particles, or anycombination thereof.

In some embodiments, the filler comprises a phyllosilicate of theserpentine group.

In some embodiments, the a phyllosilicate of the serpentine group isantigorite (Mg₃Si₂O₅(OH)₄), chrysotile (Mg₃Si₂O₅(OH)₄), or lizardite(Mg₃Si₂O₅(OH)₄).

In some embodiments, the filler comprises a clay mineral, which ishalloysite (Al₂Si₂O₅(OH)₄), kaolinite (Al₂Si₂O₅(OH)₄), illite((K,H₃O)(Al,Mg,Fe)₂(Si,Al)₄O₁₀[(OH)₂,(H₂O)]), montmorillonite((Na,Ca)_(0.33)(Al,Mg)₂Si₄O₁₀(OH)₂.nH₂O), vermiculite((MgFe,Al)₃(Al,Si)₄O₁₀(OH)₂.4H₂O), talc (Mg₃Si₄O₁₀(OH)₂), palygorskite((Mg,Al)₂Si₄O₁₀(OH).4(H₂O), or pyrophyllite (Al₂Si₄O₁₀(OH)₂).

In some embodiments, the filler comprises a phyllosilicate of the micagroup.

In some embodiments, the a phyllosilicate of the mica group is biotite(K(Mg,Fe)₃(AlSi₃)O₁₀(OH)₂), muscovite (KAl₂(AlSi₃)O₁₀(OH)₂), phlogopite(KMg₃(AlSi₃)O₁₀(OH)₂), lepidolite (K(Li,Al)₂₋₃(AlSi₃)O₁₀(OH)₂),margarite (CaAl₂(Al₂Si₂)O₁₀(OH)₂), glauconite((K,Na)(Al,Mg,Fe)₂(Si,Al)₄O₁₀(OH)₂), or any combination thereof.

In some embodiments, the filler comprises a phyllosilicate of thechlorite group.

In some embodiments, the a phyllosilicate of the chlorite group ischlorite ((Mg,Fe)₃(Si,Al)₄O₁₀(OH)₂.(Mg,Fe)₃(OH)₆).

In some embodiments, the filler forms a beehive-like structure.

In some embodiments, the beehive-like structure is microscopic.

In some embodiments, the filler comprises clay.

In some embodiments, the filler comprises zeolite.

In some embodiments, the core comprises at least about 0.05, 0.1, 0.2,0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 grams of the at least oneagrochemical. In some embodiments, the core comprises 1-10 grams of theat least one agrochemical.

In some embodiments, the core is about 30%, 35%, 40%, 45%, 50%, 55%, or60% of the at least one agrochemical by weight.

In some embodiments, weight of the bead is 1-10 g. In some embodiments,the weight of the bead is 6-7 g. In some embodiments, the weight of thebead is 3.5-4 g.

In some embodiments, the at least one core is biodegradable.

In some embodiments, the internal zone contains one core.

In some embodiments, the internal zone contains more than one core.

In some embodiments, the at least one agrochemical is:

-   -   i) at least one fertilizer compound;    -   ii) at least one pesticide compound,    -   iii) at least one hormone compound;    -   iv) at least one ding compound;    -   v) at least one chemical growth agents; and/or    -   vi) at least one microelement.

In some embodiments, the at least one fertilizer compound is a naturalfertilizer.

In some embodiments, the at least one fertilizer compound is a syntheticfertilizer.

In some embodiments, the at least one pesticide compound is:

-   -   i) at least one insecticide compound;    -   ii) at least one nematicide compound;    -   iii) at least one herbicide compound; and/or    -   iv) at least one fungicide compound.

In some embodiments, the at least one insecticide compound isimidacloprid.

In some embodiments, the at least one herbicide compound ispendimethalin.

In some embodiments, the at least one fungicide compound isazoxystrobin.

In some embodiments, the at least one nematicide compound isfluensulfone.

In some embodiments, the at least one fertilizer compound is PO₄, NO₃,(NH₄)₂SO₂, NH₄H₂PO₄, and/or KCl.

In some embodiments, the at least one fertilizer compound comprisesmultiple fertilizer compounds which include PO₄, NO₃, (NH₄)₂SO₂,NH₄H₂PO₄, and/or KCl.

In some embodiments, the at least one agrochemical is at least onefertilizer compound and at least one pesticide compound.

In some embodiments, the at least one agrochemical is at least onepesticide compound.

In some embodiments, the at least one agrochemical is at least onefertilizer compound.

In some embodiments, the at least one pesticide compound is at least onepesticide compound that is not suitable for application to anagricultural field.

In some embodiments, the at least one pesticide compound that is notsuitable for application to an agricultural field is too toxic to beapplied to an agricultural field.

In some embodiments, the at least one pesticide compound is toxic toanimals other than arthropods or mollusks when applied to anagricultural field in an amount that is sufficient to kill an arthropodor a mollusk.

In some embodiments, the at least one agrochemical is released from thecore of the internal zone over a period of at least about one week whenthe SAP of the external zone is hydrated.

In some embodiments, the at least one agrochemical is released from thecore of the internal zone over a period of at least about one week whenthe SAP of the external zone is hydrated.

In some embodiments, the at least one agrochemical is released from theinternal zone into the external zone over a period of at least about 2,3, 4, 5, 6, 7, 8, 9, 10, or 20 weeks when the SAP of the external zoneis hydrated.

In some embodiments, the at least one agrochemical is released from theinternal zone into the external zone over a period of at least about 2,3, 4, 5, 6, 7, 8, 9, 10, or 20 weeks when the SAP of the external zoneis about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or 5-50%hydrated.

In some embodiments, when the SAP of the bead is hydrated and the beadis in soil, the at least one agrochemical diffuses from the surface ofthe bead into the surrounding soil at a linear rate beginning about 25days after hydration.

In some embodiments, when the SAP of the bead is hydrated and the beadis in soil, the at least one agrochemical diffuses from the surface ofthe bead into the surrounding soil for at least about 50 or 75 daysafter hydration.

In some embodiments, the bead is not hydrated.

In some embodiments, the bead contains less than about 35%, 30%, 25%,20%, 15%, or 10% water by weight.

In some embodiments, the bead further comprises an interface zonebetween the internal zone and the external zone, which interface zone isformed by at least one insoluble salt or solid, at least onecross-linking agent, or at least one inorganic compound.

In some embodiments, diffusion between the external zone and theinternal zone is limited by altering the pH or the cation concentrationin the internal zone, the external zone, or the interface zone.

In some embodiments, diffusion between the external zone and theinternal zone is limited by altering the pH and/or cation concentrationin the internal zone or the external zone.

In some embodiments, the pH in the internal zone or the external zone isaltered by a buffer.

In some embodiments, the pH in the internal zone, the external zone, orthe interface zone is altered by a buffer.

The present invention provides a method of growing a plant, comprisingadding at least one bead of the invention to the medium in which theplant is grown.

In some embodiments, the medium in which the plant is grown comprisessoil.

In some embodiments, the medium in which the plant is grown is soil.

In some embodiments, the soil comprises sand, silt, clay, or anycombination thereof.

In some embodiments, the soil is clay, loam, clay-loam, or silt-loam.

The present invention provides a method of growing a plant, comprisingadding multiple beads of the invention to the medium of the plant,wherein the multiple beads comprise three fertilizer compounds, suchthat the total N, P, and K content as (NH₄)₂SO₂, NH₄H₂PO₄, and KCl inthe medium as part of the beads is about 25, 5, and 30 g/m²,respectively.

The present invention provides a method of generating an artificial zonewith predetermined chemical properties within the root zone of a plant,comprising:

-   -   i) adding at least two different beads to the root zone of the        plant; or    -   ii) adding at least two different beads to the anticipated root        zone of the medium in which the plant is anticipated to grow,        wherein at least one of the at least two different beads is a        bead of an embodiment of the invention.

In some embodiments, each of the at least two different beads containsat least one agrochemical that is not contained within one of the otherat least two different of beads.

In some embodiments, the plant is grown in a field.

In some embodiments, the plant is a crop plant. In some embodiments, thecrop plant is a grain or a tree crop plant. In some embodiments, thecrop plant is a fruit or a vegetable plant.

In some embodiments, the plant is a banana, barley, bean, cassava, corn,cotton, grape, orange, pea, potato, rice, soybean, sugar beet, tomato,or wheat plant.

The present invention provides an artificial environment for plantgrowth comprising two parts, wherein part A forms a continuous systemwith part B, whereas;

-   -   Part A is a controlled release reservoir of additive with a        weight of at least 0.05 gr, and wherein;    -   Part B is an artificial environment comprised of at least 90%        water when fully swelled, and its weight is at least 5 times        larger than part A.

The present invention provides an artificial environment for plantgrowth comprising two parts, wherein part A is located inside part B,whereas;

-   -   Part A is a controlled release reservoir of additive with a        weight of at least 0.05 gr, and wherein;    -   Part B is a artificial environment comprised of at least 90%        water when fully swelled, and its weight is at least 5 times        larger than part A.

In some embodiments, the artificial environment is synthesized so thatone of the moisture, pH or osmotic pressure inside the artificialenvironment is different by at least 10% from the surrounding soil; andplant roots can penetrate and grow inside the artificial environmentvolume.

In some embodiments, parts A and B are fabricated from materialsconsisting of polymers, aerogels, hydrogels, organogels, porousinorganic, porous organic material or a combination thereof.

In some embodiments, part A is selected from the group consisting oforganic polymer, natural polymer, inorganic polymer or a combinationthereof.

In some embodiments, part A also comprises components in the solidsform.

In some embodiments, part A contains fillers selected from the groupconsisting from clays, metal oxide particles, porous particles or acombination thereof.

In some embodiments, additive is selected from the group consisting ofnutrients, agrochemicals, pesticides, microelements, drugs or acombination thereof.

In some embodiments, part A comprises both structural materials andfunctional materials.

In some embodiments, part B contains no fraction of said additive, or atleast 10 times lower concentration of said additives then in Part A,when added to the soil.

In some embodiments, part B is selected from the group consisting oforganic polymer, natural polymer, inorganic polymer or a combinationthereof.

In some embodiments, part B contains fillers selected from the groupconsisting from air, porous particles or a combination thereof.

In some embodiments, the artificial environment is transported to thefield in a dry form, containing less than 30% water.

In some embodiments, the dimension of the artificial environment is atleast 30 mL in the fully swelled form.

In some embodiments, the additive concentration in Part A is at least50%.

In some embodiments, after contacting Part A and Part B, an interface isformed between the two parts by means of: the formation of insolublesalts or solids, cross linking agents, inorganic component chemistry orby altering pH or cation concentration so as to limit the diffusionbetween the two parts and the combination thereof.

In some embodiments, part A also comprises components in the solidsform.

In some embodiments, part A comprises both structural materials andfunctional materials.

In some embodiments, the distance between the artificial environment andthe plant seed is between 0.1 to 500 centimeters.

In some embodiments, the distance between the artificial environment andthe plant seed is between 0.1 to 500 centimeters. In some embodiments,the distance between the artificial environment and the plant seed isabout 0.5, 1, 15, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8,8.5, 9, 9.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 100 centimeters.

Non-limiting examples of structural materials of the present inventionare materials that give the structure of the system for example water,aerogels, treated starch, treated cellulose, polymers, superadsorbentsand the functional materials are the materials consumed by the plant forexample, a fertilizer compound.

Each embodiment disclosed herein is contemplated as being applicable toeach of the other disclosed embodiments. Thus, all combinations of thevarious elements described herein are within the scope of the invention.

It is understood that where a parameter range is provided, all integerswithin that range, and tenths thereof, are also provided by theinvention. For example, “0.2-5 mg/kg/day” is a disclosure of 0.2mg/kg/day, 0.3 mg/kg/day, 0.4 mg/kg/day, 0.5 mg/kg/day, 0.6 mg/kg/dayetc. up to 5.0 mg/kg/day.

Terms

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by a person of ordinaryskill in the art to which this invention belongs.

As used herein, and unless stated otherwise or required otherwise bycontext, each of the following terms shall have the definition set forthbelow.

As used herein, “about” in the context of a numerical value or rangemeans ±10% of the numerical value or range recited or claimed, unlessthe context requires a more limited range.

An “agrochemical zone” is a component of a unit of the invention whichcontains at least one agrochemical and which releases the at least oneagrochemical into the root development zones of a unit of the invention.In some embodiments, the at least one agrochemical is released into theroot development zones of a unit of the invention by diffusion when theroot development zones of the unit are hydrated.

The term “coating system” means one or more compounds which delays orprevents the release of an agrochemical from the surface of anagrochemical zone which is covered by the coating system. In someembodiments, the coating system comprises a single coat compound. Insome embodiments, the coating system comprises more than one coatcompound. In some embodiments, the coating system comprises more thanone layer. In some embodiments, each layer of the coating system is ofthe same composition. In some embodiments, each layer of the coatingcomposition is of a different composition. In some embodiments, thecoating system comprises two, three, or four layers.

The term “controlled release” when used to refer to an agrochemical zonemeans that the agrochemical zone is formulated to release the one ormore agrochemicals of the agrochemical zone gradually over time. In someembodiments, the agrochemical zones are formulated to release the atleast one agrochemical into the root development zones over a period ofat least about one week when the root development zones are hydrated. Insome embodiments, the agrochemical zones are formulated to release theat least one agrochemical into the root development zones over a periodgreater than one week when the root development zones are hydrated.“Controlled release” is interchangeable with the term “slow release”(“SR”).

“DAP” means days after planting.

Unless required otherwise by context, a “unit” refers to a unit fordelivery of agrochemicals to the roots of a plant as described herein. A“fertilizer unit” refers to a unit for delivery of agrochemicals to theroots of a plant as described herein which comprises a fertilizer.

An “empty unit” comprises the root development zone component of a unitof the invention unaccompanied by the agrochemical zone component. Insome embodiments, an empty unit has the same shape and/or dimensions asthe corresponding unit of the invention.

A “root development zone” is a component of a unit of the inventionwhich, when hydrated, can be penetrated by a growing root. In someembodiments, the growing root can grow and develop within the rootdevelopment zone of a unit. In some embodiments, a root development zoneis a super absorbent polymer (SAP). In some embodiments, the rootdevelopment zone is an aerogel, a geotextile, or a sponge. In someembodiments, the root development zone will take up water from thesurrounding environment when, for example, the unit is placed in soilwhich is subsequently irrigated. In some embodiments, the hydrated rootdevelopment zones create a artificial environment in which a growingroot can uptake water and nutrients. In some embodiments, the rootdevelopment zones of a unit are formulated to contain one or moreagrochemicals which are the same or different than the agrochemicals ofthe agrochemical zones of the unit. While the invention described hereinis not limited to any particular mechanism of action, it is believedthat a growing root is attracted to the root development zones of a unitbecause of the presence of water and/or agrochemicals (e.g. minerals) inthe root development zones. It is believed that roots can continue togrow and develop within the root development zones of units because ofthe continued availability of water and/or agrochemicals in the units.

Use of the term “root development zones” means one or more rootdevelopment zones and use of the term “agrochemical zones” means one ormore agrochemical zones unless stated otherwise or required otherwise bycontext.

In some embodiments, a unit of the invention is in the form of a “bead”having an “external zone” which surrounds an “internal zone.” In someembodiments, the “external zone” is a root development zone and the“internal zone” is an agrochemical zone.

Plants provided by or contemplated for use in embodiments of the presentinvention include both monocotyledons and dicotyledons. In someembodiments, a plant is a crop plant. As used herein, a “crop plant” isa plant which is grown commercially. In some embodiments, the plants ofthe present invention are crop plants (for example, cereals and pulses,maize, wheat, potatoes, tapioca, rice, sorghum, millet, cassava, barley,or pea), or other legumes. In some embodiments, the crop plants may begrown for production of edible roots, tubers, leaves, stems, flowers orfruit. The plants may be vegetable or ornamental plants. Non-limitingexamples of crop plants of the invention include: Acrocomia aculeata(macauba palm), Arabidopsis thaliana, Aracinis hypogaea (peanut),Astrocaryum murumuru (murumuru), Astrocaryum vulgare (tucumã), Attaleageraensis (Indaiá-rateiro), Attalea humilis (American oil palm), Attaleaoleifera (andaiá), Attalea phalerata (uricuri), Attalea speciosa(babassu), Avena sativa (oats), Beta vulgaris (sugar beet), Brassica sp.such as Brassica carinata, Brassica juncea, Brassica napobrassica,Brassica napus (canola), Camelina sativa (false flax), Cannabis sativa(hemp), Carthamus tinctorius (safflower), Caryocar brasiliense (pequi),Cocos nucifera (Coconut), Crambe abyssinica (Abyssinian kale), Cucumismelo (melon), Elaeis guineensis (African palm), Glycine max (soybean),Gossypium hirsutum (cotton), Helianthus sp. such as Helianthus annuus(sunflower), Hordeum vulgare (barley), Jatropha curcas (physic nut),Joannesia princeps (arara nut-tree), Lemna sp. (duckweed) such as Lemnaaequinoctialis, Lemna disperma, Lemna ecuadoriensis, Lemna gibba(swollen duckweed), Lemna japonica, Lemna minor, Lemna minuta, Lemnaobscura, Lemna paucicostata, Lemna perpusilla, Lemna tenera, Lemnatrisulca, Lemna turionifera, Lemna valdiviana, Lemna yungensis, Licaniarigida (oiticica), Linum usitatissimum (flax), Lupinus angustifolius(lupin), Mauritia flexuosa (buriti palm), Maximiliana maripa (inajapalm), Miscanthus sp. such as Miscanthus×giganteus and Miscanthussinensis, Nicotiana sp. (tabacco) such as Nicotiana tabacum or Nicotianabenthamiana, Oenocarpus bacaba (bacaba-do-azeite), Oenocarpus bataua(patauã), Oenocarpus distichus (bacaba-de-leque), Oryza sp. (rice) suchas Oryza sativa and Oryza glaberrima, Panicum virgatum (switchgrass),Paraqueiba paraensis (mari), Persea amencana (avocado), Pongamia pinnata(Indian beech), Populus trichocarpa, Ricinus communis (castor),Saccharum sp. (sugarcane), Sesamum indicum (sesame), Solanum tuberosum(potato), Sorghum sp. such as Sorghum bicolor, Sorghum vulgare,Theobroma grandifrum (cupuassu), Trifolium sp, Trithrinax brasiliensis(Brazilian needle palm), Triticum sp. (wheat) such as Triicum aestivum,Zea mays (corn), alfalfa (Medicago sativa), rye (Secale cerale), sweetpotato (Lopnoea batatus), cassava (Manihot esculenta), coffee (Cofeaspp.), pineapple (Anana comosus), citris tree (Citrus spp.), cocoa(Theobroma cacao), tea (Camellia senensis), banana (Musa spp.), avocado(Persea americana), fig (Ficus casica), guava (Psidium guajava), mango(Mangifer indica), olive (Olea europaea), papaya (Carica papaya), cashew(Anacardium occidentale), macadamia (Macadamia intergrifolia) and almond(Prunus amygdalus).

Unless stated otherwise or required otherwise by context, “swelled”means that a material has an absorbed amount of water which is at leastabout 1% of the amount of water that would be absorbed by the materialif placed in deionized water for 24 hours at 21° C. When the material isa hydrogel, a “swelled” hydrogel can be referred to as a “hydrated”hydrogel. In some embodiments, a swelled material has an absorbed amountof water which is at least about 2% of the amount of water that would beabsorbed by the material if placed in deionized water for 24 hours at21° C. In some embodiments, a swelled material has an absorbed amount ofwater which is at least about 3% of the amount of water that would beabsorbed by the material if placed in deionized water for 24 hours at21° C. In some embodiments, a swelled material has an absorbed amount ofwater which is at least about 4% of the amount of water that would beabsorbed by the material if placed in deionized water for 24 hours at21° C. In some embodiments, a swelled material has an absorbed amount ofwater which is at least about 5% of the amount of water that would beabsorbed by the material if placed in deionized water for 24 hours at21° C.

Unless stated otherwise or required otherwise by context, “hydrated”means at least about 1% hydrated. In some embodiments, “hydrated” meansat least about 2% hydrated. In some embodiments, “hydrated” means atleast about 3% hydrated. In some embodiments, “hydrated” means at leastabout 4% hydrated. In some embodiments, “hydrated” means at least about5% hydrated.

As used herein, a “fully swelled” unit of the invention is a unit whichcontains an amount of absorbed water which is equal to the amount ofwater the unit would absorb if placed in deionized water for 24 hours at21° C.

As used herein, an artificial environment means a media located withinthe root zone of an agricultural field or a garden plant loaded with atleast one agrochemical, encourages root growth and uptake activitywithin its internal periphery. Non-limiting examples of agrochemicalsinclude pesticides, including insecticides, herbicides, and fungicides.Agrochemicals may also include natural and synthetic fertilizers,hormones and other chemical growth agents.

In some embodiments, the medium may comprise multiple sub-zones, suchas:

-   -   i) an agrochemical zone (for example, an Internal Zone); and    -   ii) a root development zone (for example, an External Zone).

In some embodiments, the agrochemical zone is formulated to release theat least one agrochemical into the root development zone over a periodof at least about one week when the hydrogel of the root developmentzone is hydrated. In some embodiments, the agrochemical zone isformulated to release the at least one agrochemical into the rootdevelopment zone over a period of at least about 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 weeks when the hydrogel ofthe root development zone is hydrated. The agrochemical zone may beformulated to control the release of the at least one agrochemical intothe root development zone by a variety of means described herein. Forexample, the at least one agrochemical may be incorporated into a densepolymer in the core of the agrochemical zone, from which the at leastone agrochemical diffuses when root development zone is hydrated.Additionally, the core may be coated with a compound or compounds thatslow the rate of the at least one agrochemical's diffusion into the rootdevelopment zone. In some embodiments, the coat compound may diffuseinto the root development zone when the root development zone ishydrated, thereby slowing the rate of the at least one agrochemical'sdiffusion into and/or through the root development zone. In someembodiments, the core comprises a filler comprising the at least oneagrochemical, from which the at least one agrochemical diffuses. In someembodiments, the at least one agrochemical diffuses from the core or thefiller at a linear rate. The filler may slow the rate of the at leastone agrochemical from the core. In some embodiments filler may has aphysical structure, such as a beehive-like structure, into which the atleast one agrochemical is incorporated, and from which the at least oneagrochemical slowly diffuses. Bentonite is a non-limiting example of afiller having a beehive-like structure that is useful in embodiments ofthe present invention.

The agrochemical zone may contain the input (fertilizer or otheragrochemical) in a structure that controls its release into the rootdevelopment zone. The release rate is designed to meet plant demandsthroughout the growing season. In some embodiments, no input residualsremain at the end of a predetermined action period.

In some embodiments, the agrochemical zone comprises one or morefertilizers and/or other agrochemicals such as nitrogen, phosphorus,potassium, fungicide, insecticide, etc., in a beehive like structuremade from highly cross linked polymer coated with silica or highly crosslinked poly acrylic acid/poly sugar with a clay filler. In someembodiments, the agrochemical zone comprises fertilizer and/or at leastone other agrochemical in a beehive like structure with or without anexternal coating.

In some embodiments, the root development zone is a super absorbentpolymer (SAP) in contact with or surrounding the agrochemical zone,which attracts the growth and uptake activity of plant roots. In someembodiments, the root development zone is a super absorbent polymer-madefrom CMC-g-poly(acrylic acid)/celite composite system or modified cornstarch cross linked poly (acrylic acid). A root development zone whichsurrounds an agrochemical zone may be referred to herein as a “shell.”

Root development zones of the present invention are sustainable insoils, and encourage root penetration, uptake activity, and growthand/or development in the root development zone. In some embodiments, asuper absorbent polymer may serve as the root development zone sinceduring watering it can absorb soil moisture, swell and maintain its highwater content over long period of time. These features establish a zonewhere gradual transition of chemical concentration exists between theagrochemical zone to the periphery of the root development zone allowingroot uptake activity during the unit of the invention's life cycle. Insome embodiments, the root development zone has features such asmechanical resistance (in order to maintain its shape and geometry inthe soil); swelling cycle capability (capable of repeated hydration anddehydration in response to soil water content); oxygenpermeability—(maintaining sufficient oxygen level to support rootactivity, such as root development); and root penetration (allowing thegrowth of roots into it).

Materials that may be used in the present invention include but are notlimited to: 1) clay 2) zeolite 3) tuff 4) fly ash 5) hydrogel 6) foam.

In some embodiments, an artificial environment of the present inventionserves as a buffer for soil type and pH to provide universal root growthenvironment. In some embodiments, an artificial environment of thepresent invention contains needed materials and nutrients in the desiredconditions, such as but not limited to water, fertilizers, drugs, andother additives.

Oxygen Permeability

Aspects of the present invention relate to root development zones havingSAPs that are permeable to oxygen when hydrated. Roots use oxygen forgrowth and development (Drew, 1997; Hopkins 1950). Therefore, the oxygenpermeability of a SAP is an important factor in determining whether itwill support root growth and development within a root development zonethat comprises the SAP.

Without wishing to be bound by any scientific theory, since hydrogels ofthe present invention supply water, nutrients and weak resistance, thedata hereinbelow show that provided the gas diffusion is high enough,roots will develop in most types of small-volume hydrogels and hydrogelcontaining units, installed in a field soil. For example, alginatehydrogel, which is suitably permeable to oxygen, encourages rootdevelopment, whereas starch hydrogel, which is poorly permeable tooxygen does not encourage root development. Additionally, semi-syntheticCMC is also suitably permeable to oxygen. The ability of oxygen todiffuse into root development zones of the present invention isimportant for root development within them.

Aspects of the present invention relate to the selection of SAPs, suchas hydrogels, that are sufficiently permeable to oxygen when hydrated.Oxygen permeability may be measured to determine whether a hydrated SAPis sufficiently permeable to oxygen for use in embodiments of thepresent invention. In some embodiments, the SAP is permeable to oxygensuch that it supports root growth and/or development. In someembodiments, the SAP when hydrated is at least about 70, 75, 80, 85, 90,95, or 100% as permeable to oxygen as hydrated alginate. In someembodiments, the SAP when hydrated is at least about 70, 75, 80, 85, 90,95, or 100% as permeable to oxygen as hydrated semi-synthetic CMC.

Oxygen permeability may be measured according to assays that are wellknown in the art. Non-limiting examples of methods that may be usefulfor measuring oxygen permeability of SAPs of the invention are describedin Aiba et al. (1968) “Rapid Determination of Oxygen Permeability ofPolymer Membranes” Ind. Eng. Chem. Fundamen., 7(3), pp 497-502; Yasudaand Stone (1962) “Permeability of Polymer Membranes to Dissolved Oxygen”Cedars-Sinai Medical Center Los Angeles Calif. Polymer Div, 9 pages,available fromwww.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=AD0623983;Erol Ayranci and Sibel Tune (March 2003) “A method for the measurementof the oxygen permeability and the development of edible films to reducethe rate of oxidative reactions in fresh foods” Food Chemistry Volume80, Issue 3, Pages 423-431; and Compañ et al. (July 2002) “Oxygenpermeability of hydrogel contact lenses with organosilicon moieties”Biomaterials Volume 23, Issue 13, Pages 2767-2772, the entire contentsof each of which are incorporated herein by reference. The permeabilityof a SAP may be measured when it is partially or fully hydrated, e.g.when the SAP is 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or5-50% hydrated.

Mechanical Resistance

In preferred embodiments of the present invention, the root developmentzones of a unit of the invention are both i) sufficiently permeable tooxygen to encourage root growth, and ii) do not disintegrate in soil. Inespecially preferred embodiments, the root development zones of a unitof the invention are mechanically resistant, i.e., are capable ofrepeated swelling cycles in soil without fragmenting in the soil. Inparticularly preferred embodiments, all of the SAP of the rootdevelopment zones remains part of the root development zones afterrepeated swelling cycles.

Despite alginate's permeability to oxygen, root development zonesconsisting of alginate are not suitable in preferred embodiments of theinvention because alginate tends to disintegrate in soil. However,semi-synthetic CMC, which does not tend to disintegrate and is capableof repeated swelling cycles without fragmenting in soil (i.e., ismechanically resistant), is suitable for use in root development zonesin preferred embodiments the invention.

Implementation of Artificial Environments

Some embodiments of the present invention comprise the following phases:

Phase 1: Banding and incorporating into the upper soil profile.

Phase 2: Following watering (rainfall and/or irrigation) the rootdevelopment zones (comprising, e.g. a SAP) absorbs moisture from thesoil and swells; water penetrates the coating (if present) and dissolvesthe fertilizer and/or other agrochemical(s) which then diffuse into theroot development zones (e.g. towards the periphery of a bead).

Phase 3: Roots grow, develop, and remain in the root development zoneswhere uptake lasts a predetermined period.

Methods for Testing Properties of Root Development Zones

The following is a non-limiting example of a method that may be used totest the properties of root development zones (e.g. bead shells).

-   -   Distribute empty units (e.g. shells) of different sizes in a        pot. In some embodiments, empty units of three sizes are used.        The shells may have a dry radius of, e.g., 0.5, 1, 1.5, 2, 2.5,        3, 3.5, 4, 4.5, or 5 cm or a length of, e.g., 0.5, 1, 1.5, 2,        2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, or 10 cm. In some        embodiments a 10, 11, 12, 13, 14, 15, 20, 25, or 30 liter pot is        used. In some embodiments the empty units are distributed in the        pot with soil. In some embodiments, the soil is sandy soil.    -   Monitor the final size and geometry of the empty units following        watering. In some embodiments, the final geometry is spherical,        cylindrical, or box shaped.    -   Installing ceramic suction cups to mimic roots water uptake and        applying suction through the syringes.    -   Altering watering frequency over time (e.g., from high—few times        per day to low—once a week).    -   Monitoring the volume of water in the syringes and water drained        from the bottom of the pot over time.

The following is another non-limiting example of a method that may beused to test the properties of root development zones (e.g. beadshells),

-   -   Distribute empty units (e.g. shells) of one size (base, e.g. on        findings from the method described above phase) in a transparent        cell. In some embodiments, the cell is made of Perspex- and is        60×2×30 cm). In some embodiments, the empty units are        distributed with soil. In some embodiments, the soil is sandy        soil.    -   Monitoring root location and empty unit status. In some        embodiments, root location and empty status is monitored by        photography or/and scanning.    -   Repeat with units with/without nutrients.    -   Monitoring roots location to conclude if roots attract by        nutrients or water.    -   Altering watering frequency over time (e.g., from high—few times        per day to low—once a week).

Methods for Testing Properties of Units of the Invention

The following is a non-limiting example of a method that may be used totest the properties of root development zones (e.g. bead shells).

-   -   Growing a plant in a pot. In some embodiments, the pot is a 10,        11, 12, 13, 14, 15, 20, 25, or 30 liter pot.    -   Installing filter paper cups to monitor concentrations in the        root zone and drainage over time.

Additionally:

-   -   Growing a plant in a transparent cell with mixture of units        (e.g. beads) and soil. In some embodiments, the soil is sandy        soil.    -   Add dying agents to units which are sensitive to environmental        conditions (e.g., pH, Salinity, or N, P, and K).    -   Altering watering frequency over time (e.g. from high—few times        per day to low—once a week).

Super Absorbent Polymers

Super Absorbent Polymers are polymers that can absorb and retainextremely large amounts of a liquid relative to their own mass.Non-limiting examples of SAPs that are useful in embodiments of thesubject invention are described in K. Horie, M. Bairon, R. B. Fox, J.He, M. Hess, J. Kahovec, T. Kitayama, P. Kubisa, E. Maréchal, W.Mormann, R. F. T. Stepto, D. Tabak, J. Vohlídal, E. S. Wilks, and W. J.Work (2004). “Definitions of terms relating to reactions of polymers andto functional polymeric materials (IUPAC Recommendations 2003)”. Pureand Applied Chemistry 76 (4): 889-906; Kabiri, K. (2003). “Synthesis offast-swelling superabsorbent hydrogels: effect of crosslinker type andconcentration on porosity and absorption rate”. European Polymer Journal39 (7): 1341-1348; “History of Super Absorbent Polymer Chemistry”. M2Polymer Technologies, Inc. (available fromwww.m2polymer.com/html/history_of_superabsorbents.html); “Basics ofSuper Absorbent Polymer & Acrylic Acid Chemistry”. M2 PolymerTechnologies, Inc. (available fromwww.m2polymer.com/html/chemistry_sap.html); Katime Trabanca, Daniel;Katime Trabanca, Oscar; Katime Amashta, Issa Antonio (September 2004).Los materiales inteligentes de este milenio: Los hidrogelesmacromoleculares. Sintesis, propiedades y aplicaciones. (1 ed.). Bilbao:Servicio Editorial de la Universidad del País Vasco (UPVIEHU); andBuchholz, Fredric L; Graham, Andrew T, ed. (1997). Modern SuperabsorbentPolymer Technology (1 ed.), John Wiley & Sons, the entire contents ofeach of which are hereby incorporated herein by reference.

Non-limiting examples of hydrogels that are useful in embodiments of thesubject invention are described in Mathur et al., 1996. “Methods forSynthesis of Hydrogel Networks: A Review” Journal of MacromolecularScience, Part C: Polymer Reviews Volume 36, Issue 2, 405-430; and Kabiriet al., 2010. “Superabsorbent hydrogel composites and nanocomposites: Areview” Volume 32, Issue 2, pages 277-289, the entire contents of eachof which are hereby incorporated herein by reference.

Geotextiles

Geotextiles are permeable fabrics which are typically used to preventthe movement of soil or sand when placed in contact with the ground.Non-limiting examples of geotextiles that are useful in embodiments ofthe subject invention are described in U.S. Pat. Nos. 3,928,696,4,002,034, 6,315,499, 6,368,024, and 6,632,875, the entire contents ofeach of which are hereby incorporated herein by reference.

Aerogels

Aerogels are gels formed by the dispersion of air in a solidifiedmatrix. Non-limiting examples of aerogels that are useful in embodimentsof the subject invention are described in Aegerter, M., ed. (2011)Aerogels Handbook. Springer, the entire contents of which is herebyincorporated herein by reference.

Aerochemicals Fertilizers

A fertilizer is any organic or inorganic material of natural orsynthetic origin (other than liming materials) that is added to a plantmedium to supply one or more nutrients that promotes growth of plants.

Non-limiting examples of fertilizers that are useful in embodiments ofthe subject invention are described in Stewart, W. M.; Dibb, D. W.;Johnston, A. E.; Smyth, T. J. (2005). “The Contribution of CommercialFertilizer Nutrients to Food Production”. Agronomy Journal 97: 1-6.;Erisman, Jan Willem; MA Sutton, J Galloway, Z Klimont, W Winiwarter(October 2008). “How a century of ammonia synthesis changed the world”Nature Geoscience 1 (10): 636.; G. J. Leigh (2004). The world's greatestfix: a history of nitrogen and agriculture. Oxford University Press US,pp. 134-139; Glass, Anthony (September 2003). “Nitrogen Use Efficiencyof Crop Plants: Physiological Constraints upon Nitrogen Absorption”.Critical Reviews in Plant Sciences 22 (5): 453; Vance; Uhde-Stone &Allan (2003), “Phosphorus acquisition and use: critical adaptations byplants for securing a non renewable resource”. New Phythologist(Blackwell Publishing) 157 (3): 423-447.; Moore, Geoff (2001).Soilguide—A handbook for understanding and managing agricultural soils.Perth, Western Australia: Agriculture Western Australia. pp. 161-207;Hitussinger, Peter; Reiner Lohmiiller, Allan M. Watson (2000). Ullmann'sEncyclopedia of Industrial Chemistry, Volume 18. Weinheim, Germany:Wiley-VCH Verlag GmbH & Co. KGaA. pp. 249-307.; Carroll and Salt, StevenB. and Steven D. (2004). Ecology for Gardeners. Cambridge: TimberPress.; Enwall, Karin; Laurent Philippot, 2 and Sara Hallin1 (December2005). “Activity and Composition of the Denitrifying Bacterial CommunityRespond Differently to Long-Term Fertilization”. Applied andEnvironmental Microbiology (American Society for Microbiology) 71 (2):8335-8343.; Birkhofera, Klaus; T. Martijn Bezemerb, c, d, Jaap Bloeme,Michael Bonkowskia, Søren Christensenf, David Duboisg, Fleming Ekelundf,Andreas Flieβbachh, Lucie Gunstg, Katarina Hedlundi, Paul Mäderh, JuhaMikolaj, Christophe Robink, Heikki Setäläj, Fabienne Tatin-Frouxk, WimH. Van der Puttenb, c and Stefan Scheua (September 2008). “Long-termorganic farming fosters below and aboveground biota: Implications forsoil quality, biological control and productivity”. Soil Biology andBiochemistry (Soil Biology and Biochemistry) 40 (9): 2297-2308.; Lal, R.(2004). “Soil Carbon Sequestration Impacts on Global Climate Change andFood Security”. Science (Science (journal)) 304 (5677): 1623-7.; andZublena, J. P.; J. V. Baird, J. P. Lilly (June 1991).“SoilFacts—Nutrient Content of Fertilizer and Organic Materials”. NorthCarolina Cooperative Extension Service. (available fromwww.soil.ncsu.edu/publications/Soilfacts/AG-439-18/), the entirecontents of each of which are hereby incorporated herein by reference.

Non-limiting examples of fertilizers which may be useful in embodimentsof the present invention include Ammonium nitrate, Ammonium sulfate,anhydrous ammonia, calcium nitrate/urea, oxamide, potassium nitrate,urea, urea sulfate, ammoniated superphosphate, diammonium phosphate,nitric phosphate, potassium carbonate, potassium metaphosphate, calciumchloride, magnesium ammonium phosphate, magnesium sulfate, ammoniumsulfate, potassium sulfate, and others disclosed herein.

Pesticides

Pesticides are substances or mixtures of substances capable ofpreventing, destroying, repelling or mitigating any pest. Pesticidesinclude insecticides, nematicides, herbicides and fungicides.

Insecticides

Insecticide are pesticides that are useful against insects, and includebut are not limited to organochloride, organophosphate, carbamate,pyrethroid, neonicotinoid, and ryanoid, insecticides.

Non-limiting examples of insecticides that are useful in embodiments ofthe subject invention are described in van Emden H F, Pealall D B (1996)Beyond Silent Spring, Chapman & Hall, London, 322 pp; Rosemary A. Cole“Isothiocyanates, nitriles and thiocyanates as products of autolysis ofglucosinolates in Cruciferae” Phytochemutry, 1976. Vol. 15, pp. 759-762;and Robert L. Metcalf “Insect Control” in Ullmann's Encyclopedia ofIndustrial Chemistry” Wiley-VCH, Weinheim, 2002, the entire contents ofeach of which are incorporated herein by reference.

Nematicides

Nematicides are pesticides that are useful against plant-parasiticnematodes.

Non-limiting examples of nematicides that are useful in embodiments ofthe subject invention are described in D. J. Chitwood, “Nematicides,” inEncyclopedia of Agrochemicals (3), pp. 1104-1115, John Wiley & Sons, NewYork, N.Y., 2003; and S. R. Gowen, “Chemical control of nematodes:efficiency and side-effects,” in Plant Nematode Problems and theirControl in the Near East Region (FAO Plant Production and ProtectionPaper—144), 1992, the entire contents of each of which are incorporatedherein by reference.

Herbicides

Herbicides are pesticides that are useful against unwanted plants.Non-limiting examples of herbicides that are useful in embodiments ofthe subject invention include 2,4-D, aminopyralid, atrazine, clopyralid,dicamba, glufosinate ammonium, fluazifop, fluroxypyr, imazapyr,imazamox, metolachlor, pendimethalin, picloram, and triclopyr.

Fungicides

Fungicides are pesticides that are useful against fungi and/or fungalspores.

Non-limiting examples of fungicides that are useful in embodiments ofthe subject invention are described in Pesticide Chemistry andBioscience edited by G. T Brooks and T. R Roberts. 1999. Published bythe Royal Society of Chemistry; Metcalfe, R. J. et al. (2000) The effectof dose and mobility on the strength of selection for DMI (steroldemethylation inhibitors) fungicide resistance in inoculated fieldexperiments. Plant Pathology 49: 546-557; and Sierotzki, Helge (2000)Mode of resistance to respiration inhibitors at the cytochrome bc1enzyme complex of Mycosphaerella fijiensis field isolates PestManagement Science 56:833-841, the entire contents of each of which areincorporated herein by reference.

Microelements

Non-limiting examples of microelements that are useful in embodiments ofthe subject invention include iron, manganese, boron, zinc, copper,molybdenum, chlorine, sodium, cobalt, silicon, and selenium nickel.

Hormones

Plant hormones may be used to affect plant processes.

Non-limiting examples of plant hormones that are useful in embodimentsof the subject invention include but are not limited to, auxins (such asheteroauxin and its analogues, indolylbutyric acid and a-naphthylaceticacid), gibberellins, and cytokinins.

All publications and other references mentioned herein are incorporatedby reference in their entirety, as if each individual publication orreference were specifically and individually indicated to beincorporated by reference. Publications and references cited herein arenot admitted to be prior art.

This invention will be better understood by reference to theExperimental Details which follow, but those skilled in the art willreadily appreciate that the specific experiments detailed are onlyillustrative of the invention as defined in the claims which followthereafter.

EXPERIMENTAL DETAILS

Examples are provided below to facilitate a more complete understandingof the invention. The following examples illustrate the exemplary modesof making and practicing the invention. However, the scope of theinvention is not limited to specific embodiments disclosed in theseExamples, which are for purposes of illustration only.

Example 1 The External Zone

Four specific criteria were defined as the following, where eachcondition was tested experimentally:

-   -   Mechanical resistance—maintain shape and geometry in the soil    -   Swelling cycles—hydrate and dehydrate in corresponds to soil        water content    -   Oxygen permeability—maintain sufficient oxygen level to root        activity    -   Root penetration—allows the growth of root into it.

Mechanical resistance was tested by flushing water throughout acontainer filled with SAP and sand soil, Initial, final weights anddimensions were recorded. A pass mark was accepted for SAP thatmaintains a single element and didn't wash away or split into severalparts. Three groups of SAP were synthesized and tested:

SAPs Group Poly sugar Semi synthetic Fully synthetic Type AlginateCMC-g-poly (acrylic acid)/Celite Acrylic composite system CarboxymethylAcid/Acryl cellulose grafted polyacrylics acid Amide with Celite as afiller. k-Carrageenan poly(acrylic acid)SAP

Each type of SAP was formulated with variable mixture of poly sugars,crosslinked agents, filler and additive. Moreover, samples were ovendried and immersed in distilled water in order to calculate theequilibrium swelling (ES) according to the following equation:

${ES} = \frac{{{weight}\mspace{14mu} {of}\mspace{14mu} {swollen}\mspace{14mu} {gel}} - {{weight}\mspace{14mu} {of}\mspace{14mu} {Dried}\mspace{14mu} {gel}}}{{weight}\mspace{14mu} {of}\mspace{14mu} {Dried}\mspace{14mu} {gel}}$

Table 1 summarizes the findings of the mechanical resistance tests:

Bis- SAP-Group SAP-type AAm/AA % PS/AA NaOH ES Semi- CMC 0.75-1.25 50-7515-25  73-467 synthetic k-Carrageenan 1.6-2.5 33-66 — 25-72 Poly sugarAlginate-2% — 100 — 38 Fully Acrylic —  0 — 180 synthetic (AA/AM)“Bis-AAm/AA” means (Acrylic acid crosslinked with Bis acrylamide,” “%PS/AA, semi-synthetic Polysugar - acrylic acid hydrogel” and “ES” means“equilibrium swelling.” “Alginate-2%.” means 2% in water when hydrated.

1) Poly Sugar:

-   -   16 gr of sodium alginate was dissolved in 800 ml distilled water        at 50° C. using mechanical stirrer (1000 RPM). Then 20 gr from        the alginate solution was added in to 50 ml beaker, then 10 gr        of 0.1 M solution of CaCl₂, was added in to the beaker (CaCl₂        served as the cross-linking agent). The beads were left in the        solution for 12 hr.

2) CMC-g-Poly (Acrylic Acid)/Celite

-   -   Various amounts of CMC (Carboxymethyl cellulose sodium Salt)        (0.5-2 g) were dissolved in 25 ml distilled water and were added        to a 100 ml beaker with magnetic stirrer. The beaker was        immersed in a temperature controlled water bath preset at 80° C.        After complete dissolution of CMC, various amounts of Celite        powder (0.3-0.6 g in 5 ml water) were added (if any) to the        solution and allowed to stir for 10 min. Then, certain amounts        of AA (Acrylic Acid) (2-3 ml) and MBA (N—N methylene bis        acrylamide) (0.025-0.1 g in 5 ml water) were added to the        reaction mixture and allowed to stir for 5 min. Then the        initiator solution (0.07 g APS (Ammonium persulfate) in 5 ml        water) was added to the mixture, the mixture was placed immersed        in a temperature controlled water bath preset at 85° C. for 40        minutes to complete polymerization. To neutralize (0-100%)        acrylic groups, appropriate amount of NaOH (0-1 gr in 5 ml        water) was added. The obtained gel was poured to excess        nonsolvent ethanol (80 ml) and remained for 1 h.        3) k-Carrageenan (kC) Cross-Linked-Poly(Acrylic Acid)

0.5-1 gr of kC (k-Carrageenan) was dissolved in 25 mL of distilledwater, which was under vigorous stirring in a 100 ml beaker with amagnetic stirrer. The flask was immersed in a temperature controlledwater bath at 80° C. After complete dissolution of kC to form ahomogeneous solution, certain amounts of AA (Acrylic Acid), and MBA (N—Nmethylene his acrylamide) simultaneously added to the reaction mixture.Afterward, the solution was stirred and purged with nitrogen for 2 minto remove the dissolved oxygen. Then, a definite amount of APS (Ammoniumpersulfate) solution was added dropwise to the reaction flask undercontinuous stirring to generate free radicals. The reaction maintainedat this temperature for 1 h to complete polymerization.

4) Fully Synthetic System (a Sample for AAm):

AAm (Acrylamide) (10 g) was mix with 25 ml distilled water at roomtemperature in a 50 ml beaker equipped with magnetic stirrer. Then MBA(N—N methylene his acrylamide) (0.008 gr) was added into the mixture andallowed to stir for 10 min. Then an initiator solution was added (0.07 gSPS (Sodium persulfate)). The mixture was placed into 5 ml template (4gr solution each) and placed in a convention furnace (85° C.) for 20min. The product was washed overnight with ethanol (80 ml) to obtain thepolymerized shell.

Starch Systems—Sample for Non-Growing Media 1) Modified StarchCross-Linked Poly(Acrylic Acid)

1-2.5 gr of Corn starch dissolved in deionized 20 ml water in 100 mlbeaker at room temperature. The combination was mixed until a uniformmixture was formed. 2-3 gr AA (Acrylic acid) was added to the cooledmixture and the resulting mixture was stirred for five minutes. Next,1-3 gr AAm (acrylamide) was added to the mixture, and the resultingmixture was stirred for five minutes. Then 0.005-0.01 gr of MBA (N—Nmethylene bis acrylamide) dissolved in 5 ml of deionized water was addedto the mixture, and the resulting mixture was stirred for five minutes.Lastly, 0.005 gr of APS (ammonium persulfate) dissolved in 0.5 ml ofdeionized water; was added to the mixture and the resulting mixture wasstirred while being heated to 80° C. The mixture was held at thattemperature and stirred for approximately 15 minutes. Because theresulting viscous mass was acidic, the mixture was neutralized bytitration with 45% potassium hydroxide (KOH) at room temperature.Titration continued until a pH of 7.0 was reached, which requiredaddition of between about 0.2-16 g 45% KOH.

2) Similar Process to the CMC-AA System.

(Exchanging CMC with Corn-Starch):

-   -   1 gr of corn Starch was dissolved in 25 ml distilled water and        were added to a 100 ml beaker with magnetic stirrer. The beaker        was immersed in a temperature controlled water bath preset at        80° C. Then 2 ml of AA (Acrylic Acid) and MBA (N—N methylene bis        acrylamide) (0.015 g in 5 ml water) were added to the reaction        mixture and allowed to stir for 5 min. Then the initiator        solution (0.07 g APS (Ammonium persulfate) in 5 ml water) was        added to the mixture, the mixture was placed immersed in a        temperature controlled water bath preset at 85° C. for 40        minutes to complete polymerization. NaOH (0.5 gr in 5 ml water)        was added in order to neutralize acrylic groups. The obtained        gel was poured to excess nonsolvent ethanol (80 ml) and remained        for 1 h.

Swelling cycles of selected formulations in water and two types of soilwere tested. The ability of the SAPs to absorb water in relatively shorttime is an important physical property that allows maintaining itsfunctionality in the soil throughout its life cycle. The followinggraphs present the swelling behavior of the different SAPs uponhydration-dehydration cycles in water. The ES of the investigated SAPsstay constant during three cycles, meaning good mechanical properties.

The water content of several SAPs in sandy silica soil was measuredfollowing watering over a time period that is a typical watering cycleof crops and plants. The various SAPs gain water from the soil in thefirst 24 hours following by a mild decrease/increase over the next 125hours. When SAPs were introduced to air dry loess soil, initially itwent under rapid de hydration, yet watering the soil reverse the processand water were absorbed from the soil the soil recovery percentage were99 and 50. The results indicate that all groups of SAPs can maintaintheir moisture in the sandy soil over a watering cycle and that CMC baseSAPs can fully recovery from extreme dry condition in soil.

Oxygen permeability of the SAPs was studied by measuring dissolvedoxygen in water that was exposed to oxygen saturated water across a SAP,Altering dissolved oxygen level was done by bubbling nitrogen or oxygengases into the water reservoir located opposite the sensor, SAPs madefrom Alginate and CMC showed an order magnitude more oxygen permeabilitythan SAP of k-carrageenan (FIG. 4).

Dissolved Oxygen Test:

Oxygen electrode place into a pre-swelled hydrogel in a 100 ml beaker.The dissolved oxygen inside the hydrogel was measured during N₂ bubblingor O₂ bubbling (˜0.5 liter per minute) as a function of time.

The O₂ measurements made by Lutron WA2017SD Analyzer with dissolvedoxygen probe 0-20 mg/L, 0-50° C. The Dissolved Oxygen System is shown inFIG. 13.

Root penetration was evaluated visually from a series of experiments,where various crops grew in pots filled with organic soil surrounded anartificial environment. Table 2 summarizes the observations presented inFIG. 10:

Roots Roots Roots on the penetrated developed surface of into in theartificial the artificial artificial SAPs Crop environment environmentenvironment Poly Sugar- Pea − + + Alginate Semi synthetic- Corn,Pea, + + − CMC Semi synthetic- Pea + + − k-Carrageenan Fully syntheticCorn + + −

Example 2 The Internal zone

Three mechanisms were developed and evaluated to address the criteria ofi) release rate of agrochemicals from the internal zone over a growingseason, and ii) that no input residuals remain at the end of apredetermined action period. All the three, are based on integrating theinput into a very dense polymer as the basic mechanism to slow downdiffusion, in conjunction to a secondary mechanism that willadditionally decrease the diffusion rate:

-   -   1) Highly Cross Linked Polymer with silicon coating (xLP-Si);    -   2) Highly Cross linked Poly Acrylic/poly sugar with filler        (xLP-F); and    -   3) Hybrid system (SiCLP-).

The first mechanism is based on precipitation of silica, originated fromsilica water, on the surface of the polymer (FIG. 4).

The second mechanism is based on filler, made from bentonite, integratedinto the polymer and decreases sharply its diffusion properties (FIG.6).

The third mechanism is to mix the silica with the acrylic whilesynthesizing the polymer in order to alter its diffusion coefficient(FIG. 7).

The reduction in diffusion properties by each mechanism wasexperimentally tested. The internal zone was located in a free waterreservoir where the concentration of a certain input (Nitrogen orPhosphorus) was measured over time.

The release of nitrate from cornstarch internal zone with (blue) andwithout (red) silica coating is presented in FIG. 7. A reduction ofdiffused nitrate was measured in the first 24 hours.

Alternatively, the mixed silica mechanism yielded release of nitrate andphosphorus in the scale of weeks, as well.

Example 3 Stability, Dimensions, and Mechanical Resistance of HydrogelsApplied to a Field Plot Objective

The objective of this example was to study the sustainability in soil,hydrated dimensions and mechanical resistance of different types andsizes of hydrogel within a field plot. Furthermore, root penetrationinto these types of hydrogels was studied.

Hydrogels

The types and sizes of hydrogels are described in Table 3 below:

Small Medium Large (hydrated (hydrated size (hydrated size No. Chemicalcomposition size of 2-3 cm) of 4-5 cm) of 7-8 cm) Geometry 1 Fullysynthetic + Box 2 Semisynthetic CMC 6% + + + Cylinder/Box/Cylinder AAm 3Semisynthetic CMC 6% AA + Box 4 Semisynthetic CMC 25% + Box AA 5Semisynthetic CMC 50% + + + Cylinder/Box/Cylinder AA 6 PolysugarsAlginate + Cylinder

The fully synthetic hydrogel had the composition of the fully synthetichydrogel described in Example 1.

The semisynthetic CMC 6% AAm hydrogel comprises 6% CMC relative to theacrylic acid monomers (Acrylamide-acrylic) and was made by the followingprocess. 0.25 g AA was mixed with 4.5 ml distilled water at roomtemperature in a 50 ml beaker equipped with a magnetic stirrer. Then 0.1g NaOH, 0.01 g MBA, 0.75 g AAm and 1.5 gr CMC solution (3.8% w/w) wereadded into the mixture and allowed to stir for 10 minutes. Then aninitiator solution comprising 0.1 g SPS was added. The mixture wasplaced into a 5 ml template (4 g solution for each shell) and placed ina convention furnace at 85° C. for 20 minutes. The product was washedovernight with 80 ml ethanol to obtain the polymerized shell.

The semisynthetic CMC 6% AA hydrogel comprises 6% CMC relative toacrylic acid and was made by the following process. 1 g AA was mixedwith 4.5 ml distilled water at room temperature in a 50 ml beakerequipped with magnetic stirrer. Then 0.4 g NaOH, 0.01 g MBA and 1.5 gCMC solution (3.8% w/w) were added to the reaction mixture and allowedto stir for 10 minutes. Then 0.1 g of SPS was added. The mixture wasadded into a 5 ml template (4 g solution for each shell), and thetemplate was placed in a convention furnace at 85° C. for 20 minutes.The product was washed overnight with 80 ml ethanol to obtain thepolymerized shell.

The semisynthetic CMC 25% AA hydrogel comprises 25% CMC relative toacrylic acid and was made by the following process. 2 g AA was mixedwith 12.5 g CMC solution (3.8% w/w) at room temperature in a 50 mlbeaker equipped with magnetic stirrer. Then 0.01 g MBA was added intothe mixture and allowed to stir for 10 minutes. Then an initiatorsolution comprising 0.1 g SPS was added. The mixture was placed into 5ml template (4 gr solution for each shell), and the template was placedin a convention furnace at 85° C. for 20 min. Then NaOH (0.728 molarratio or 0.8 gr in 50 ml water) was added to the polymerization product.The product was then washed overnight with 80 ml ethanol to obtain thepolymerized shell.

The semisynthetic CMC 50% AA hydrogel comprises 50% CMC relative toacrylic acid and was made by the following process. 1.5 g CMC weredissolved in 35 ml distilled water and added to a 100 ml beaker withmagnetic stirrer. The beaker was immersed in a temperature controlledwater bath preset at 85° C. After complete dissolution of CMC, thebeaker was placed on a magnetic stirrer at room temperature with N₂bubbling at a flow rate of ˜0.5 LPM. Then 3 g AA and 0.03 g MBA wereadded to the reaction mixture and allowed to stir for 20 minutes and thetemperature was allowed to decrease to 35° C. Then the 0.03 g of theinitiator SPS in 1 ml water was added. The mixture was placed into 5 mltemplate (4 g solution for each shell) and placed in furnace at 85° C.for 20 minutes. Then NaOH (0.728 molar ratio or 0.8 gr in 50 ml water)was added to the polymerization product. The product was then washedovernight with 80 ml ethanol to obtain the polymerized shell.

The polysugars alginate hydrogel had the composition of the polysugarhydrogel described in Example 1.

Experimental Setup

The experiment took place at the Southern Arava R&D station. A 125square meters field plot, divided to 4 beds×15 m long was served to test3 application methods, six types and three sizes of hydrogels. Rootpenetration was studied in plot D.

The experimental setup is shown in FIG. 14.

The three application conditions for plots A-C were:

i) Uniform application in loose soil—to mimic conventional beds forvegetable crops;ii) Uniform application in compacted soil—to mimic conventional beds forvegetable crops, with compaction; andiii) Application in a furrow—to mimic a furrow in field row crops.

A one square meter or one linear meter sub plots (50 cm apart) were usedto apply 27 units of each hydrogel (plots A-C). The units were uniformlydistributed on the soil surface and incorporated into the upper 15 cm ofthe soil profile. Similarly, a 20 cm deep furrow was dug and 27 unitswere distributed along one meter. Water was applied through a solidsprinkler set without fertilizer (1 m³=8 mm).

The roots penetration plot (plot D) consisted of a 15 m long bed, where25 hydrogels from each type were applied along a 1 m furrow of 20 cmdeep. Maize was sown above the at the same day and was irrigated with asolid set of sprinklers without fertilizes, that was switched aftergermination to a drip line (25 cm spacing, 2 l/h) with Idit liquidfertilizer (100 mg/l N). Irrigation was shut off on day 31 and wasopened again one day before soil excavation. Visual dimensionalmeasurements and qualitative information on root penetration werecollected on day 50.

Measurements included individual weight, dimension and tension of 3units. Timing of water application to plots A-C and measurements areshown in Table 4 below:

Day Irrigation (mm) Measurements 0 Application 1 160 2 1^(st) 5 40 62^(nd) 8 40 12 40 3^(rd) (before irrigation) 16 4^(th) 29 5^(th)

Climate during the experiment was clear sky with no rainfall. Maximumand minimum soil temperatures at 5 cm depth during the experiment periodare presented in FIG. 15. The hydrogels were exposed to temperatureswhich ranged between 10° C. at night to 40° C. around midday.

Results for Plots A-C

Changes in weight for each hydrogel type and size versus time are shownin FIG. 16. The variable soil moisture was derived by the irrigationevents (vertical bars). During the wetting phase, comprising of fourconsecutive irrigations (day-12), most of the hydrogels gained weight byabsorbing soil water. The poly sugar Alginate was the only type to loseweight throughout the experiment, although soil moisture fluctuatedbetween very wet to mild dry soil. While medium and large hydrogelsmultiplied their own weight (equal to the amount of absorbed soil water)by 5-11 times, the small hydrogel grew by 18 times. During the 16 daysdrying phase, hydrogels lost weight by 2-4 times (of the originalweight) to the drying soil. No correlation between CMC percentage andwater absorbance was found. This may imply that local conditions aremore dominant than chemical composition.

The final surface area derived from the volume and the geometry of thehydrogels is shown in FIG. 17. Initial areas ranged between 25-30 cm²for medium size, 35 cm² for large size and 10 cm² for small size. Mostmedium hydrogels experienced a minor increase, up to 35 cm², whileAlginate decreased sharply and Semisynthetic CMC 50% AA (no. 5)increased dramatically to 60 cm². The two large sizes increased to over50 cm². Surface area of hydrogel units versus time is shown in FIG. 18.

The ratio between surface areas to volume was constant to most hydrogelsat the value of 2.5-3. The poly sugar Alginate and both small sizehydrogels had high ratio due to their relatively small dimensions.Surface area to volume ratios for the hydrogels are shown in FIG. 19.

The distance between a chemical (positioned inside the hydrogel) and theadjacent soil determines the diffusion rates towards the soil. Theminimal distance stands for the smallest edge of the hydrogel geometry.Moreover, the same value describes the potential zone for root growth.The initial minimal distance was in the range of 1-2 cm and final valuesincreased to 1.5-2.5 cm. This entails that a chemical will need todiffuse 1-2 cm prior to reaching the soil. The poly sugar Alginateshrunk over time, reaching 0.5 cm in width. The small size hydrogel wasdifficult to follow, yet it stretched to 0.75 cm. Final minimaldistances of the hydrogels are shown in FIG. 20. FIG. 21 shows theminimal distance of hydrogel units versus time.

Stiffness is an important parameter related to the potential of roots topenetrate the media and the potential of water to be absorbed.Measurements of stiffness were achieved by using a penetrometer gaugeand a metal disc. The values shown in FIGS. 22 and 23 are in relativescale, representing the force that was required to push the disc on thesurface of the hydrogel. No differences between medium and large sizeswere found. The poly sugar Alginate was consistently very stiffthroughout the experiments, contrary to the fully synthetic, which wasrelatively flexible. A negative trend between CMC content and level ofstiffness was observed.

A photo of each hydrogel at the end of the experiment is shown in FIG.24. The Fully synthetic, Semisynthetic CMC 6% AAm, Semisynthetic CMC 25%AA maintained the original box shape. Similarly, Semisynthetic CMC 6%AAm-Large, Semisynthetic CMC 50% AA-Large and Semisynthetic CMC 6%AAm-Small maintained the cylindrical geometry. Several hydrogels, madefrom Semisynthetic CMC 6% AA, disintegrated into small particles.Semisynthetic CMC 50% AA lost its original box geometry and turned intoan undefined geometry. The poly sugars Alginate turned into a flat disc.

Results for Plot D

Hydrogels nos. 6, 9 and 10 could not be found in the root zone at theend of the experiment. Photos of each hydrogel type at the end of theexperiment are shown in FIG. 25. The left photo shows the hydrogelsin-situ and the right shows a few samples where roots penetrated throughit. Fully synthetic, Semisynthetic CMC 6% AAm, and Semisynthetic CMC 25%AA maintained the original box shape. Similarly, Semisynthetic CMC 6%AAm-Large and Semisynthetic CMC 50% AA-Large maintained theircylindrical geometry. Several hydrogels, made from Semisynthetic CMC 6%AA, disintegrated into small particles. Semisynthetic CMC 50% AA lostits original box geometry and turned into an undefined geometry. Alltypes of hydrogel experienced shrinkage relative to its maximum volumemeasured in the bare soil plots. Roots penetrated into all types ofhydrogels. While course roots penetrated into the Fully synthetic,Semisynthetic CMC 25% AA and Semisynthetic CMC 50% AA hydrogels, onlyfine roots were found in the Semisynthetic CMC 6% AAm, Semisynthetic CMC6% AA and Semisynthetic CMC 6% AAm-Large.

Summary

Six types and three sizes of hydrogels were tested in a field plotduring wetting and drying periods. Most of them were in accordance withsoil moisture, absorbing water (up to 10 times their initial weight) inthe first period and releasing water in the second one. Final surfacearea was 30-50 cm². The minimal dimension of the medium and largehydrogels was 1.5-2.5 cm, allowing sufficient volume for rootpenetration. Small hydrogels expanded to less than 1 cm, which wouldconstrain the amount of chemicals which could be encapsulated within thehydrogel. Stiffness was evaluated and a major difference was foundbetween hydrogel types. While most types maintained their original 3Dgeometry, a few disintegrated or deformed.

Six types and three sizes of hydrogels were evaluated in a field plotfor root penetration. Most types maintained their original 3D geometry,yet a few disintegrated, deformed or flushed away. Roots penetrated intoall hydrogels, but a few types had only fine roots while others had fineand course roots. The amount of root penetration and developmentobserved in the different size hydrogels suggests that a minimum volumeof hydrogel is required for root penetration and development.

Example 4 Performance of Hydrogels Loaded with Fertilizer in DifferentSoil Types

Example 3 demonstrated the ability of hydrogels to sustain in the fieldsoil under wet and drying cycles. Moreover, roots penetrated into thehydrogels suggesting the potential use to deliver chemicals directly toroots. Current practices to deliver fertilizers to the plant rootsmostly involve application of fertilizers to the soil, a highly variablemedia (physically, chemically and biologically). Such practices yieldlow efficiency of fertilizer uptake.

Objective

The primary objective was to study the effectiveness of hydrogels loadedwith fertilizer (fertilizer units) to supply plant uptake requirementsthroughout the growing season. The secondary objective was to test thedevelopment of fine roots, dominant in mineral uptake, within thehydrogel.

Fertilizer Units

The composition of the fertilizer units of Example 4 was as shown inTable 5:

% w/w Fertilizer units - composition Osmocote ® Start 6 Weeks 14%Polymer 86% Polymer composition Acrylic Acid 3% Acryl-Amide 8%CarboxyMethyl Cellulose sodium <1% salt Sodium Persulfate 1% N—Nmethylene bis acrylamide <1% Water 74%

Experimental Setup

The experiment took place at the Southern Arava R&D station. Twentythree rotating weighing lysimeters (FIG. 26) served to test thefertilizer units versus fertigation (Fert.) and slow release fertilizer(SR, Osmocote® Start 6 Weeks, Everris). The system allowed accuratemonitoring of quantity and quality of irrigation and drainage water andplant water uptake. Fertilizer units, containing 0.625 g of the slowrelease fertilizer (N:P:K ratio by weight was12:4.8:14.1+micronutrients), were distributed evenly at three depths:30, 20 and 10 cm (FIG. 27). Total weight of each unit during applicationwas 6-7 g.

Sunflowers were used as a model plant. Two sunflowers were grown in eachlysimeter. The lysimeters were irrigated daily (clay soil-twice a week)at an average rate of 200% of measured actual Evapotranspiration (ET).The high leaching factor was designed to minimize drought and salinityeffects.

The experiment was divided into three stages:

Stage 1: Comparing the application of slow released fertilizer tofertilizer units.

Stage 2: Separating between water and fertilizer effect on plantdevelopment.

Stage 3: Evaluating the fertilizer unit performance in different soiltypes.

The experimental setup is shown in Table 6:

Fertilizing Fertilizing rate vs. plant Lysimeters soil technologyrequirement nos. Note Stage Dune fertilizer unit 100% (Full) 12, 13, 1490 fertilizer 1 sand units fertilizer unit  50% (Half) 15, 16, 17 45fertilizer units SR 100% (Full) 4, 5, 6 None Stage Dune fertilizer unit100% (Full) 9, 10 45 fertilizer 2 sand units Empty unit + 100% (Full) 7,8 45 Empty Fert. units Stage Grow- fertilizer unit 100% (Full) 1 45fertilizer 3 ing unit Media SR 100% (Full) 21 45 fertilizer units Clayfertilizer unit 100% (Full) 18 45 fertilizer units SR 100% (Full) 3 45fertilizer units

Stage 1

The sunflowers were sown on day 0 and harvested on day 33. Dune sand wasselected due to its inerratic properties, minimizing adsorption to clayminerals and precipitation due to low bicarbonate content. Applicationdose of N, P and K per plant for each treatment is depicted in FIG. 28.Plant height, no. of leaves, Soil Plant Analysis Development (SPAD)values and NPK in drainage water were recorded at points during thegrowing season. Final yield quantification included dry biomass and NPKcontent of the whole plant. Following harvest, the fertilizer units wereexcavated and NPK content was quantified.

Stage 2

The sunflowers were sown on day 0 and harvested on day 36. Applicationdose of N, P and K per plant for each treatment was half of the valuesdepicted in FIG. 28. Plant height, no. of leaves, SPAD values wererecorded at points during the growing season. Final yield was evaluatedas wet biomass.

Results Stage 1

Plant height, number of leaves and its N content, represented by SPADvalues, throughout the growing season are presented in FIG. 29.

Differences in height and leaves between the fertilizer units and SRstarted from the beginning of the growing season and continued till theend (see FIG. 35). SPAD values were higher during the main nutrientapplication period (DAP 20-45). The lower SPAD values measured at theend of the growing season for fertilizer unit treatment were attributedto earlier maturity, where nutrients are being transferred from theleaves to the seeds.

Plant dry matter, absolute NPK uptake amount and its efficiency arepresented in FIG. 30. The fertilizer units yielded larger plants and NPKuptake versus the Slow Release fertilizer. Within the fertilizer unittreatment, the full fertilization achieved higher plants and uptake, yetthe efficiency was equal. The greatest fertilizer use efficiency of thefertilizer unit demonstrates the advantage of the new technology overcurrent best practices.

Relative residuals of NPK in the fertilizer units are depicted in FIG.31. The lower values, less than 6%, indicate that most of the fertilizerwas taken up by the plant or diffused to the soil.

Stage 2

The dune sand, used in stage 1, has a low water holding capacity andhigh hydraulic conductivity, meaning that daily irrigation may notoptimize day time plant water availability. The hydrogel's shell has thepotential to improve water availability by absorbing water duringirrigation and release it later at dry periods. Therefore, it waspossible that the significant differences found in stage 1 could relateto two factors, namely fertilizers and water availability. Therefore, acomparison between fertilizer units and empty fertilizer units installedin the root zone & fertigation (Empty units+Fert.) was conducted instage 2.

Plant height, no. of leaves, SPAD value along the growing season and wetbiomass from each treatment are presented in FIG. 32. Plants exposed tofertilizer units were advantageous over empty units+Fert at allparameters (see FIG. 35), suggesting that water availability plays aminor role relative to fertilizer supply under the experimentalconditions. Plants which were fertilized by fertilizer units exhibitedfaster growth and enhanced biomass production.

Stage 3

The main drawbacks the invention overcomes in soils are:

-   -   Diminishing leaching, adsorption and precipitation of ions.    -   Maintaining high diffusion rate at variable moisture conditions.    -   Minimizing root growth resistance.    -   Allowing continuous biological activity.    -   Improving water holding capacity.

These drawbacks can be overcome by replacing the soil with growingmedia, which is considered to provide the best conditions for plantgrowth. This hypothesis was tested by comparing the fertilizer units, SRand Fert. fertilization methods. The performance of fertilizer units inheavy clayey soil was tested at the 3rd stage.

Plant height, no. of leaves, SPAD value along the growing season and wetbiomass for each treatment are presented in FIG. 33. No significantdifferences were measured between treatments (see FIG. 35), suggestingthat growing media generates similar properties as fertilizer units.

Plant height, no. of leaves, SPAD value along the growing season and wetbiomass for each treatment are presented in FIG. 34. Visual results ofExample 4 are shown in FIG. 35. Fertilizer units improved plant growthcompared to SR (see FIG. 35), demonstrating that fertilizer units areadvantageous in various soil types.

Summary

The study demonstrated the ability of the fertilizer units to delivernutrients to plants throughout the growing season in various soils.Moreover, fertilizer units enhanced plant growth and final yield. Thehigher fertilizer use efficiency over current practice was due tovarious reasons:

-   -   Extensive growth of active roots adjacent to the fertilizer        source (See FIG. 35).    -   Limited leaching from the fertilizer unit due to lack of mass        flow across it.    -   Maintaining high diffusion rates within the fertilizer unit in        drying soil due to steady high moisture levels (unlike soil).

Since the release rate of the fertilizer in this experiment wastemperature dependent, the extreme high temperature which existed in thesoil (average max. soil temp of 45.3° C.) enhanced the diffusion rateand therefore the absolute efficiency values were relatively low (FIG.30).

Roots did not penetrate empty units, probably due to a lack offertilizer within the hydrogel and sufficient moisture for plant uptake.

The uptake efficiency shown in FIG. 30 represents the ratio between theamount of fertilizer applied to the amount taken up by the plant. Thehigher uptake efficiency values observed for the fertilizer unitscompared to traditional SR fertilizer (FIG. 30) suggests that lessleaching of fertilizer towards groundwater occurs when fertilizer isapplied using fertilizer units.

Example 5 Comparison of Fertilizer Units to Slow Released Fertilizer andFertigation in Sunflower and Cabbage Objective

The objective was to study the effectiveness of hydrogel loaded with SRfertilizer (fertilizer units) as a method of supplying plant nutritionalrequirements throughout the growing season under field conditions.

Experimental Setup

The experiment took place in a field plot located in the Western Galileein Israel (N 33, E55). The site is characterized with heavy alluvialsoil, rich in clay minerals, which induces high cation exchange capacity(≈50 meq/100 g), high pH (≈8) and intermediate salinity salinity (EC ofsaturated paste-0.5 dS/m). Dry weather conditions with mostly clearskies (average direct radiation—670 W/m²) were prevalent throughout theexperiment. Maximum and minimum air and soil temperatures, middayrelative humidity and day time during the trial are presented in Table7:

Max. Min. Air temp. (° C.) 34.2-24.5 34.2-24.5 Soil temp. (° C.)32.1-11.4 Midday Relative humidity (%) 71-12 Day time (hh:mm)13:41-10:29

A 150 square meter plot was divided into subplots based on randomizedblock design (FIG. 36). To ensure initial low levels of soil nitrogen(N), millet was grown on the field plot without complementaryfertilization for 30 days prior to trial initiation. The fertilizerunits were compared to fertigation (Fert.—Urea based) and to slowreleased fertilizer application (SR, Osmocote® Start 6 Weeks, Everris).Equal irrigation and N quantities were applied to all treatments.Nitrogen application rates were based on literature values, wherecabbage was reported to utilize 3.6 g of N per plant and sunflower wasreported to utilize 3 g of N per plant. Plants were irrigated twice aweek based on ET measurements and literature values for plant covercoefficient. Irrigation of sunflowers was ceased two weeks priorharvesting. The crops were planted on day 0 with planting densities of40,000 plants per hectare. The cabbage was harvested on day 70 andsunflower was harvested on day 89.

The monitoring plan (Table 8) included plant development parametersthroughout the growing season and final yield analysis. Data wascollected from pre-marked plants, six plants in the middle row (cabbage)and 6-10 plants which exhibited similar development stage after twoweeks (sunflower).

TABLE 8 Developing Yield Crop Pre-plant parameters analysis Post-harvestCabbage Soil NPK Plant diameter Wet weight of Soil N content* head andleaves content* No. of leaves Dry weight of head and leaves Headdiameter N content in head and leaves*** Sunflower NPK content in leavesPlant height Wet weight of flower and leaves No. of leaves Dry weight offlower and leaves Flower N content in diameter flower*** SPAD values**Weight of dry seeds NPK content in leaves *SM3500K and SM4500P-NO; **Chlorophyll content optical sensor- Minolta, SPAD 502B;***kjeldahl-colorimetric

Fertilizer Application

Fertilizer units, weighing 6-7 g and containing 1 g of SR (N:P:K ratioby weight was 12:4.8:14.1+micronutrients), were evenly distributed attwo depths: 25 and 15 cm. Total fertilizer unit application was 80 units(80 grams) per meter length for the cabbage and 100 for sunflower. SRwas distributed evenly at similar rates and depth. The cabbagefertigation treatment was set to weekly applications of Urea-N withirrigation water, following a predetermined plan base on literaturevalues of plant N requirement. The sunflower fertigation treatment wasexecuted similarly, with the total plant N requirement applied duringthe first two weeks.

Results

Averages and standard deviations (fertilizer units only) of sunflowerheight, cabbage leaf diameter, number of leaves and SPAD values(sunflower only) throughout the growing season are presented in FIG. 37.Differences were measured between the fertilizer units, SR andfertigation treatments in height, diameter, leaf number and SPAD (seeTable 9) at variable stages and maintained until the end. The improvedparameters suggested enhanced growth conditions under fertilizer unitapplication for both crops.

TABLE 9 Statistical groups (Anova) Fertilizing method Crop Parameterfertilizer unit SR Fert. P Sunflower Height A A A 0.562 Leaves A B B<0.001 SPAD A B B <0.001 Grains yield A A A 0.537 N uptake A A A 0.696Cabbage Leaves A B B 0.005 diameter Leaves A B B 0.005 Yield A B AB0.242 Biomass A AB B 0.005 N uptake A A B 0.004

Leaf nutrient content was measured at 55 days after planting, where bothcrops finalized their vegetative growth. No significant differences werefound between treatments. Plants under fertilizer unit application didnot exhibit nutritional deficiencies relative to traditional fertilizerapplication methods at this stage of growth (FIG. 38).

The development of cabbage yields (FIG. 39B) was evaluated from thelinear ratio between head diameter and its weight (FIG. 39A). Theadvantage of the fertilizer unit application was most noticeable 60-70days after planting.

Final yield analysis of cabbage biomass and N uptake for fertilizer unitversus conventional fertilizer application methods is shown in FIG. 40,Significant differences were measured between the fertilizer unit andfertigation treatments, implying that nutrients are less available forplant uptake using conventional fertilizing methods.

The final yield analysis of sunflower showed similar grain yield and Nuptake by plants fertilized by the fertilizer unit application methodrelative to conventional fertilizer application methods (FIG. 41).Although no significant difference was measured, plants exposed tofertilizer units uptake more N than plants exposed to conventionalfertilizing methods.

Residuals of NPK in 10 fertilizer units from each plot are depicted inFIG. 42. Nitrogen residuals were less than 2%, P less than 8% and K Lessthan 2.5%. These values indicate that most of the fertilizer was takenup by the plants or diffused into the soil.

Residuals of N in the root zone (upper 30 cm of soil profile) of eachcrop are presented in FIG. 43. Nitrogen accumulation in the root zonewas tenfold higher in the sunflower plots and 4 times higher in thecabbage plots.

Nitrogen mass balance was calculated in the root zones of cabbage andsunflower (FIG. 44). Fertilizer units exhibited higher N uptakeefficiency over conventional fertilizing techniques, suggesting enhancedavailability of fertilizers to plant uptake within the fertilizer units.

Summary

This study demonstrated the ability of the fertilizer units to delivernutrients to plants throughout the growing season under normal fieldconditions. Moreover, fertilizer units enhanced plant growth (sunflowerand cabbage) and increased the final yield (especially cabbage) comparedto current practice. The higher N use efficiency over current practicesis attributed to the following reasons:

-   -   1. Extensive growth of active roots adjacent to the fertilizer        source (determined visually).    -   2. Limited leaching from the fertilizer units due to lack of        water flow across it.    -   3. Maintaining high diffusion-dispersion rates within the        fertilizer units in drying soil due to steady high moisture        levels over time (unlike soil).

Example 6 Pilot Scale Production of Fertilizer Units Based on AA-AAm-CMCHydrogels with Onsmocote® 6 Weeks Cores

This Example describes the production of fertilizer units useful in themethods of the invention.

Materials

Acrylic Acid (AA) (Sigma Aldrich catalog #147230)

Acrylamide (AAm) (Acros catalog #164830025)

N—N methylene his acrylamide (MBA) (Sigma Aldrich catalog #146072)

Carboxymethylcellulose Sodium salt MW=90K (CMC) (Sigma Aldrich catalog#419273)

Sodium persulfate (SPS) (Sigma Aldrich catalog #216232)

Deionized water (DIW)

Osmocote® start 11-11-17+2MgO+TE, Everris International B.V. (Scott).

Methods

8 kg of a 3.8% w/w CMC stock solution is made by slowly adding 304 g ofCMC powder to 7,696 g of 90° C. DIW followed by stirring for 12 hours at50° C. Additional DIW is added to replace any water which evaporatesduring the 12 hours of stirring.

12 kg of a pre-monomer solution is made by first making an AA solutionby slowly adding 336 g of AA to 5,990 g of DIW, then adding 384 g of KOH50% (w/w) solution, and mixing the solution for 15 minutes at 36° C. andpH 4.7. 1,009 g of AAm and 10.09 g MBA is then added to the AA solutionand mixed for 15 minutes. 4,238 g of a 3.8% CMC stock solution is thenadded to the solution and the solution is mixed for 30 minutes toprovide the pre-monomer solution.

2 L of a monomer solution with initiator is made by adding 4.5 g of SPSinto 2 kg of the pre-monomer solution and mixed for 20 minutes.

The fertilizer units are made in two polymerization steps. In the firststep, a bowl-like hydrogel structure is made by adding 4 ml of themonomer solution to a beads pattern using a multi-tip dosing devise. Thebeads pattern is then covered with a cones matrix and placed in afurnace at 85° C. for 60 minutes, thereby forming the bowl-like hydrogelstructure. 1 g of Osmocote® beads are then added to the bowl-likestructures. In the second polymerization step, an additional 3.5 ml ofmonomer solution is added to the beads pattern using the multi-tipdosing device. The beads pattern is then placed in a furnace at 85° C.for 60 minutes, thereby forming the complete fertilizer unit.

The fertilizer units are removed from the beads pattern and washed withethanol for 10 minutes (50 beads in 1 L ethanol). The fertilizer unitsare then washed with water for 10 minutes (50 beads in 1 L ethanol). Thefertilizer units are then dried at room temperature to a final weight of3.5-4 g. Beads produced using the above process are shown in FIG. 46.

A bead produced using the above process swells to 90-100 g when placedin 200 ml DIW for 24 hours and swells to 35-50 g when placed in 200 mlsaline water (0.45% NaCl by weight) for 24 hours. FIG. 47 shows a fullyswelled fertilizer unit produced by the above process compared to afully dried fertilizer unit.

Example 7 Performance of Fertilizer Units Under Low Ambient TemperatureGrowth Conditions Objective

The objective was to determine the ability of fertilizer units toimprove plant survival under low ambient temperatures.

Experimental Setup

Fertilizer units similar to those described in Example 6 were added atdepths of 10 and 20 cm to 80 L pots filled with sand and clay soils.Cucumber plants were grown in the pots for 63 days within a net house.Control plants were grown under same conditions with fertilizerssupplied as liquid with the irrigation water rather than as fertilizerunits.

Results

Enhanced heat capacity of the root zone, due to the fertilizer unitapplication, was demonstrated to improve plant survival under lowambient conditions as shown in Table 10.

TABLE 10 Heat capacity Minimum ambient of temperature during No. offertilizer Plant experiment Soil fertilizer units survival DAP* C.° typeunits** (Kcal/gC.°) rate 1-7; 8-12 4-5 Sand 0 0 27/36- 75% 18-28; 12-177-8 Sand 56 1380 31/36- 86% 29-36; 45-55; 56-63  9-10 Clay 0 0 19/36-53% 37-44 11 Clay 83 1380 27/36- 75% *DAP, Day after planting. **Averagevalue. Fertilizer units contained 25 g of water.

Example 8 Fertilizer Units as Fertilizer Source for Plants in VolcanicOrigin Soil and Tropical Climate

A field trial was conducted in Cartago, Costa-Rica (N9.862039,W83.898665). Local soil is classified as Andisol, a volcanic origin soilwith graded soil particle distribution (Sand—50%, Silt—20% andClay—30%), low pH (5.5), low salinity level (electrical conductivity—0.1mS/cm), low CEC (13.5 meq/L) and high organic matter (3.1%). The climateis defined as tropical with a high annual precipitation rate (400-600 cmper year), high humidity and steady high temperatures (26-11° C.).

Celery and Lettuce seedlings, representative leafy crops, weretransplanted on Day 0. The crops were fertilized by fertilizer unitssimilar to the type described in Example 6 or solid commercialfertilizer (YaraMila™ Hydrocomplex 12:11:18+Mg+Micro).

Amounts of fertilizer units and solid commercial fertilizer werecalculated so that all plants received equal amounts of nitrogen: 2.5and 3 g of N per plant for celery and lettuce, respectively. Thirtythree fertilizer units per meter at 25 cm deep and 66 fertilizer unitsper meter at 15 cm deep were applied in the celery plot. Eighty threefertilizer units per meter at 15 cm deep were applied in the lettuceplot. Solid fertilizer was applied after plant transplantation.

Marketable yield of each crop was evaluated on Day 45. FIG. 48 presentsthe combined marketable yield of celery and lettuce. Data is presentedas cumulative percentage of yield relative to control median of eachtreatment. Plants fertilized with fertilizer units were significantlylarger compared to plants fertilized with the commercial solidfertilizer.

Example 9 Microbial Examination of Fertilizer Units

A laboratory analysis of microbial colonies on the surface and insidefertilizer units was conducted to measure the transport of microbialcommunities from the soil to the fertilizer unit surface and into theinternal zone.

Microbial activity is required in controlling urea mineralization andenhancing biodegradability of the product. Fertilizer units werecollected from the root zone of the experiments described in examples 5and 7. The number of microbial colonies was measured on the fertilizerunit surface and within the internal zone after roots penetrated anddeveloped within it. A control group included new fertilizer units thatwere not in contact with soil and plant roots. High concentration ofmicrobial colonies was found on the surface and within the internal zonefor both soil types and experimental conditions. Surface concentrationsfor fertilizer units ranged between 2.2×10⁴ to 2.9×10⁵ CFU/cm². Internalzone concentrations for fertilizer units ranged between 3.5×10⁶ to1.3×10⁵ CFU/0.1 g. Internal zone concentrations for new fertilizer units(control) were below 10 CFU/1 g. The results suggested unrestrictedtransport of microbial communities from the soil towards the fertilizerunit surface and its inner zone.

Materials and Methods

The outside of the fertilizer units were washed with running tap waterfor about one minute and then washed with sterile water. Each washedsample was placed into a sterile bag containing 100 mL of sterile waterand manually shaken for about 3 minutes. The rinsing liquid inappropriate dilutions was examined for microbial count. The fertilizerunit samples were then aseptically cut and about 0.1 g of inner contentswas removed, transferred to a tube with 10 mL of sterile water andvortexed for extraction of microorganisms. The extract was diluted andexamined for microbial count. Microbial count was determined using thepour plate method with tryptic soy broth and incubation at 30-35° C. fortwo days. After incubation the number of microbial colonies was counted.

Discussion

High rates of inefficient agrochemical use are attributed to unknownroot distribution, spatial variability in soil structure and texture(i.e. mineral and organic matter content), temporal variability of soilconditions (i.e. temperature, moisture, pH, aeration and salinity),temporal changes in plant demands of fertilizers and agrochemicals (i.e.species, development stage, root morphology), and climatic fluctuationsthroughout the growing season (i.e. rainfall, temperature, humidity,radiation and wind).

Soil-less medium, where optimal conditions for efficient uptake by rootsare maintained, is implemented solely in small scale containers ingreenhouses. This practice is not feasible as a solution for large scalefields.

An overall goal of the present invention is supplying fertilizers andother agrochemicals (e.g. nitrogen, phosphorus, potassium, fungicides,insecticides, etc.) directly to plant roots at required amounts andtiming regardless of soil and crop types and conditions.

Availability and uptake of fertilizer from commercial products aredramatically affected by soil due to the pH and reactions with variouscations. The present invention relates to universal additives andformulations that are not affected by soil type or pH, due to theformation of an artificial environment.

A problem with the additions of small SAP beads (super absorbent polymerwith diameter of 1 cm) is a fast diffusion of the additives into thesoil. In contrast to the SAP beads that are currently used, the unit fordelivery of agrochemicals to the roots of a plant of the presentinvention have a bigger size (in some embodiments, a fully hydratedvolume greater than 600 ml), which prevents this problem. Aspects of thepresent invention also prevent properties from changing due to saltsentering the soil. Furthermore, the concepts herein based on theformation of an artificial environment in the field, in contrast toother technology that use hydrogels as a solid replacement.

The an artificial environment formed by the units of the presentinvention encourages root growth and development within the unit, whichenhances and promotes efficient nutrient uptake. Thus, plants fertilizedusing the units of the present invention can grow faster and/or producea greater yield than crops fertilized by traditional methods. Theartificial environment formed by the units of the present inventionmitigates the effects of suboptimal soil conditions by, for example,providing a root development zone which minimizes root growthresistance, provides nutrients, maintains moisture levels, and protectsfrom the effects of low ambient temperature.

Aspects of the present invention that are advantageous and unique overcurrent technologies and practices include but are not limited to:

-   -   Universality—embodiments of the present invention are not        dependant on temporal and spatial variations of soil, crop and        weather.    -   Simplicity—embodiments of the present invention relate to a        single application using conventional equipment.    -   Economy—embodiments of the present invention save labor and the        amount of agrochemical input (fertilizers and        otheragrochemicals, and energy) for the farmer.    -   Sustainability—embodiments of the present invention protect the        environment (water bodies and atmosphere) from contamination as        a result of leaching, runoff and volatilization of        agrochemicals.    -   Yield—embodiments of the present invention enhance plant growth        rates and yield.

The present invention provides artificial environments that encourage orpromote root growth or development in different soil types. Root growthand development are a function of moisture, oxygen, nutrients andmechanical resistance. The data herein showed that alginate preformedmarkedly well with respect to root development. However, additionalformulations (semi-synthetic CMC and fully synthetic-acrylic acid andacrylamide) show root growth as well. Aspects of the present inventionrelate to artificial environments that provide, moisture and nutrients,while being mechanically resistant and permeable to oxygen. The dataherein described herein demonstrated the ability of the units of theinvention to deliver water and nutrients to plants throughout thegrowing season leading to enhanced plant growth. The data describedherein further demonstrated that the units of the invention can be usedto successfully deliver nutrients to plants in variable soil types andvariable climate conditions.

REFERENCE

-   Drew M. C., 1997. Oxygen deficiency and root metabolism: Injury and    acclimation under hypoxia and anoxia. ANNUAL REVIEW OF PLANT    PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY Volume: 48 Pages: 223-250.-   Habarurema and Steiner, 1997. Soil suitability classification by    farmers in southern Rwanda. Geoderma Volume 75, Issues 1-2, Pages    75-87-   Hopkins H. T., 1950. Growth and nutrient accumulation as controlled    by oxygen supply to plant roots. Plant Physiology, 25(2): 193-209.-   Nicholson S. E. and Farrar T. J., 1994. The influence of soil type    on the relationships between NDVI, rainfall, and soil moisture in    semiarid Botswana. I. NDVI response to rainfall. Remote Sensing of    Environment Volume 50, Issue 2, Pages 107-120-   Shaviv A., Mikkelsen R. L. 1993. Controlled-release fertilizers to    increase efficiency of nutrient use and minimize environmental    degradation—A review. Fert. Res. 35, 1-12.

1. A unit for delivery of agrochemicals to the roots of a plant comprising: i) one or more root development zones, and ii) one or more agrochemical zones containing at least one agrochemical, wherein the agrochemical zones are formulated to release the at least one agrochemical into the root development zones in a controlled release manner when the root development zones are swelled, and wherein the weight ratio of the root development zones to the agrochemical zones in a dry unit is 0.05:1 to 0.32:1 or wherein the total volume of the root development zones in the unit is at least 0.2 mL when the unit is fully swelled.
 2. (canceled)
 3. (canceled)
 4. (canceled)
 5. The unit of claim 1, wherein the weight ratio of the root developments zones to agrochemical zones in a dry unit is 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, or 0.3:1.
 6. The unit of claim 5, wherein the total volume of the root development zones in the unit is at least at least 0.2 mL, at least 0.5 mL, at least 1 mL, at least 2 mL, at least 5 mL, at least 10 mL, at least 20 mL, at least 30 mL, at least 40 mL, at least 50 mL, at least 60 mL, at least 70 mL, at least 80 mL, at least, 90 mL, at least 100 mL, at least 150 mL, at least 200 mL, at least 250 mL, at least 300 mL, at least 350 mL, at least 400 mL, at least 450 mL, at least 500 mL, at least 550 mL, at least 600 mL or larger than 600 mL when the unit is fully swelled.
 7. (canceled)
 8. (canceled)
 9. The unit of claim 5, wherein roots of a plant are capable of growing within the root development zones when the root development zones are swelled, and wherein the total volume of the root development zones when the unit is 1%-100% swelled is large enough to contain at least 10 mm of a root having a diameter of 0.5 mm.
 10. (canceled)
 11. The unit of claim 1, wherein the unit has a dry weight of 0.1 g to 20 g and wherein the total weight of the agrochemical zones of the unit is 0.05 to 5 grams.
 12. (canceled)
 13. The unit of claim 1, wherein the unit is in the shape of a cylinder, polyhedron, cube, disc, or sphere.
 14. (canceled)
 15. (canceled)
 16. (canceled)
 17. (canceled)
 18. The unit of claim 1, wherein the agrochemical zones and the root development zones are adjoined, or wherein the agrochemical zones are partially contained within the root development zones such that the surface of the unit is formed by both the root development zones and the agrochemical zones.
 19. (canceled)
 20. The unit of claim 18, wherein the unit is a bead comprising an external zone surrounding an internal zone, wherein the root development zones form the external zone and the agrochemical zones form the internal zone.
 21. The unit of claim 20, wherein the unit comprises one root development zone and one agrochemical zone.
 22. The unit of claim 21, wherein the root development zones comprise a super absorbent polymer (SAP).
 23. The unit of claim 22, wherein the root development zones are capable of absorbing at least about 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 80, 85, 90, 95, 100, 200, 300, 400, 500, or 1000 times their weight in water.
 24. The unit of claim 23, wherein the root development zones are permeable to oxygen, or wherein the root development zones comprise an aerogel, a hydrogel or an organogel, or wherein the root development zones further comprise a polymer, a porous inorganic material, a porous organic material, or any combination thereof.
 25. (canceled)
 26. (canceled)
 27. (canceled)
 28. (canceled)
 29. (canceled)
 30. The unit of claim 20, wherein the agrochemical zones further comprise an aerogel, a hydrogel, an organogel, a polymer, a porous inorganic material, a porous organic material, or any combination thereof.
 31. (canceled)
 32. (canceled)
 33. (canceled)
 34. (canceled)
 35. (canceled)
 36. (canceled)
 37. (canceled)
 38. (canceled)
 39. (canceled)
 40. The unit of claim 30, wherein the root development zones comprise a synthetic hydrogel, a natural carbohydrate hydrogel, or a pectin or protein hydrogel, or any combination thereof.
 41. The unit of claim 40, wherein the root development zones comprise a natural super absorbent polymer (SAP), a poly-sugar SAP, a semi-synthetic SAP, a fully-synthetic SAP, or any combination thereof, or wherein the root development zones further comprise at least one oxygen carrier that increases the amount of oxygen in the root development zones compared to corresponding root development zones not comprising the oxygen carrier.
 42. (canceled)
 43. The unit of claim 41, wherein the agrochemical zones comprise an organic polymer, a natural polymer, or an inorganic polymer, or any combination thereof.
 44. The unit of claim 1, wherein the agrochemical zones are partially or fully coated with a coating system that dissolves into the root development zones when the root development zones are swelled and slows the rate at which the at least one agrochemical dissolves into the root development zones when the root development zones are swelled.
 45. (canceled)
 46. (canceled)
 47. (canceled)
 48. The unit of claim 1, wherein the at least one agrochemical is: i) at least one fertilizer compound; ii) at least one pesticide compound, iii) at least one hormone compound; iv) at least one drug compound; v) at least one chemical growth agents; vi) at least one enzyme; vii) at least one growth promoter; and/or viii) at least one microelement.
 49. A method of growing a plant, comprising adding at least one unit of claim 1 to the medium in which the plant is grown.
 50. (canceled)
 51. (canceled)
 52. A method of generating an artificial zone with predetermined chemical properties within the root zone of a plant, comprising: i) adding one or more units to the root zone of the plant; or ii) adding one or more units to the anticipated root zone of the medium in which the plant is anticipated to grow, wherein at least one of the one or more units is as defined in claim
 1. 